Intelligent hollow slab bottom plate thickness automatic detection equipment

Abstract

The utility model relates to the technical field of bridge nondestructive testing, especially to a kind of intelligent hollow slab bottom plate thickness automatic detection equipment, including unmanned aerial vehicle, stabilizing mechanism, knocking mechanism and sound wave acquisition mechanism;Stabilizing mechanism includes mounting plate and multiple telescopic legs, mounting plate is connected to unmanned aerial vehicle top, multiple telescopic legs are symmetrically arranged on mounting plate, pressure sensor and distance sensor are provided on telescopic leg;Knocking mechanism is installed on mounting plate by support, for carrying out mechanical knocking to bottom plate;Sound wave acquisition mechanism includes sound shield, sound collector, inflatable sealing ring and air pump, sound shield one end surrounds and is sealedly connected in the periphery of support, the other end is equipped with opening, sound collector is installed in the inner wall of sound shield, sealing ring is arranged in the opening end edge of sound shield, air pump is connected with sealing ring;It can offset the reaction force of knocking, insulate noise interference, realize the efficient, accurate, quantitative detection of hollow slab bottom plate thickness.

Description

Technical Field

[0001] This utility model relates to the technical field of non-destructive testing of bridges, and in particular to an intelligent automatic detection device for the thickness of hollow slab bottom plates. Background Technology

[0002] Hollow slab girder bridges are widely used in small and medium-span bridges in my country due to their well-defined structural stress, mature construction technology, and significant economic advantages. Statistics show that hollow slab girder bridges account for over 60% of highway bridge systems, making them one of the most representative bridge types in my country's highway construction. However, with the increasing service life of bridges, the combined effects of natural environmental factors, continuous traffic growth, and increased vehicle loads have led to increasingly prominent longitudinal cracking in the bottom slab of hollow slab girders, especially in prestressed hollow slab girders using the pre-tensioned method. These cracks not only weaken the load-bearing capacity of the components but also affect the durability of the prestressing tendons, posing a potential threat to the structural safety and service life of the bridge. Investigations of bridges that have already cracked indicate that excessively high design void ratios, misaligned core mold positioning, and insufficient bottom slab thickness due to core mold bulging are among the key factors causing longitudinal cracks in the bottom slab. Therefore, accurately determining the thickness of the bottom slab of prestressed hollow slab girders is of great significance for assessing the load-bearing capacity and durability of bridges, as well as for the scientific formulation of maintenance strategies.

[0003] Currently, the non-destructive testing of hollow slab base plate thickness mainly employs the impact method. Traditional impact methods heavily rely on operator experience, subjectively judging thickness by listening to the impact sound or feeling the rebound, resulting in low efficiency, poor consistency, and unquantifiable results. While some existing technologies combine impact components with drones, the reaction force generated when the hammer strikes the base plate causes the drone to shake, leading to impact position deviation and unstable sound wave acquisition, ultimately affecting testing accuracy. Furthermore, vibrations from the equipment's own motor, drone rotor noise, and environmental noise contaminate the impact sound wave signal collected by the microphone, resulting in a low signal-to-noise ratio, making it difficult for the sound wave processor to accurately extract effective features. Utility Model Content

[0004] To solve the above-mentioned technical problems, this utility model provides an intelligent automatic detection device for the thickness of hollow slab bottom plate that can offset the impact reaction force and isolate noise interference.

[0005] This utility model discloses an intelligent automatic detection device for the thickness of hollow slab base plates, comprising a drone, a stabilizing mechanism, a striking mechanism, and a sound wave acquisition mechanism. The stabilizing mechanism, striking mechanism, and sound wave acquisition mechanism are all connected to the drone's controller. The stabilizing mechanism includes a mounting plate and multiple telescopic legs. The mounting plate is connected to the top of the drone, and the multiple telescopic legs are symmetrically arranged on the mounting plate. Pressure sensors and distance sensors are installed on the telescopic legs, which can contact the base plate to form a stable working platform to counteract the striking reaction force. The striking mechanism is mounted on the mounting plate via a bracket and is used to mechanically strike the base plate. The sound wave acquisition mechanism includes a soundproof enclosure, a sound collector, an inflatable sealing ring, and an air pump. One end of the soundproof enclosure is surrounded and sealed to the outside of the bracket, while the other end has an opening. The sound collector is installed on the inner wall of the soundproof enclosure, and the sealing ring is located at the edge of the opening end of the soundproof enclosure. The air pump is connected to the sealing ring, allowing the sealing ring to expand and form a seal with the base plate surface during detection.

[0006] As a preferred embodiment of this utility model, at least three telescopic legs are provided, each telescopic leg including an electric telescopic rod and a foot pad at its end, and a pressure sensor is provided between the electric telescopic rod and the foot pad.

[0007] As a preferred embodiment of this utility model, the striking mechanism includes a guide, a striking block, and an electromagnetic drive unit; the guide is mounted on a bracket, and its axis is perpendicular to the plane of the mounting plate; the striking block is slidably connected to the guide, and a limiting block corresponding to the striking block is provided at the end of the guide; the striking block is made of a magnetic material, and the electromagnetic drive unit is coaxially arranged with the guide and located on the side of the striking block away from the limiting block, for driving the striking block to move along the guide.

[0008] As a preferred embodiment of this utility model, the soundproof cover has a double-layer structure, with sound-absorbing material filling the interlayer; and / or, the soundproof cover is made of wave-transparent material.

[0009] As a preferred embodiment of this utility model, at least two sound collectors are evenly distributed along the circumference of the inner wall of the soundproof enclosure.

[0010] As a preferred embodiment of this invention, the wall thickness of the sealing ring near the inner side of the soundproof enclosure is greater than that on the side farther away; this naturally creates a deformation tendency towards the central axis of the soundproof enclosure. This ensures that the inner edge of the sealing ring is pressed more preferentially and tightly against the potentially uneven base plate surface, forming a more effective seal and preventing sound leakage from the contact surface.

[0011] As a preferred embodiment of this utility model, the sound wave acquisition mechanism also includes a vent valve, which is disposed on the inflation chamber of the sealing ring.

[0012] As a preferred embodiment of this utility model, the sound wave acquisition mechanism also includes a pressure sensor, which is disposed in the inflation chamber of the sealing ring or in the air line connecting the air pump and the sealing ring.

[0013] Compared with the prior art, the beneficial effects of this utility model are as follows: The stabilizing mechanism's multiple symmetrical telescopic legs contact the base plate to form a rigid working platform. Combined with precise control from pressure and distance sensors, this system works in synergy with the upward lift provided by the drone to counteract the reaction force generated during the striking mechanism's operation. This prevents the striking position from shifting due to drone movement and ensures the stability of the acoustic wave acquisition. The striking mechanism employs a combination of electromagnetic drive and guide components to achieve standardized control of striking force and position, laying the foundation for quantitative analysis of the test results. The acoustic wave acquisition mechanism uses a double-layer sound-absorbing and sound-insulating cover and an inflatable sealing ring to form a sealed acquisition space. This isolates the drone's rotor noise and environmental noise interference. Combined with multiple circumferentially distributed sound collectors, this improves the signal-to-noise ratio of the acoustic wave signal, facilitating the processor's accurate extraction of thickness-related characteristic parameters. Attached Figure Description

[0014] Figure 1 This is a schematic diagram of the structure of this utility model; Figure 2 This is a partial structural schematic diagram of the present invention; The attached diagram is labeled as follows: 1. Unmanned Aerial Vehicle (UAV); 2. Stabilizing Mechanism; 21. Mounting Plate; 22. Telescopic Leg; 221. Pressure Sensor; 222. Distance Sensor; 223. Electric Telescopic Rod; 224. Foot Pad; 3. Striking Mechanism; 31. Bracket; 32. Guide Component; 321. Limiting Block; 33. Striking Block; 34. Electromagnetic Drive Unit; 4. Sound Wave Acquisition Mechanism; 41. Soundproof Cover; 42. Sound Collector; 43. Sealing Ring; 44. Air Pump; 45. Air Release Valve; 46. Air Pressure Sensor. Detailed Implementation

[0015] To make the above-mentioned objectives, features and advantages of this utility model more apparent and understandable, the specific embodiments of this utility model will be described in detail below with reference to the accompanying drawings.

[0016] Many specific details are set forth in the following description in order to provide a full understanding of the present invention. However, the present invention may also be implemented in other ways different from those described herein. Those skilled in the art can make similar extensions without departing from the spirit of the present invention. Therefore, the present invention is not limited to the specific embodiments disclosed below.

[0017] Reference Figure 1This embodiment provides an intelligent automatic detection device for the thickness of hollow slab bottom plate, including a drone 1, a stabilizing mechanism 2, a striking mechanism 3, and a sound wave acquisition mechanism 4. The stabilizing mechanism 2, the striking mechanism 3, and the sound wave acquisition mechanism 4 are all mounted on the drone 1 and are all connected to the controller of the drone 1. The drone 1, as a mobile carrier, can carry each mechanism to flexibly reach different detection positions on the bottom plate of the bridge hollow slab. Its controller can receive feedback signals from the sensors of each mechanism and output control commands to realize the automated linkage of the detection process.

[0018] Specifically, refer to Figure 2 The stabilizing mechanism 2 includes a mounting plate 21 and multiple telescopic legs 22. The mounting plate 21 is connected to the top of the UAV 1 and serves as the supporting base for the entire testing equipment. The multiple telescopic legs 22 are symmetrically arranged on the mounting plate 21, and each telescopic leg 22 is equipped with a pressure sensor 221 and a distance sensor 222. The pressure sensor 221 is used to monitor the contact pressure between each telescopic leg and the base plate in real time, while the distance sensor 222 is used to measure the extension length of the telescopic leg. Based on the data fed back by these sensors, the controller can adjust the extension amount of each telescopic leg 22 to ensure that the mounting plate 21 remains horizontal and maintains a predetermined distance from the base plate surface, thereby providing a stable reference plane for striking and sound wave acquisition. During operation, the telescopic legs 22 extend upward and contact the hollow plate base plate to be tested, thereby forming a rigid working platform together with the mounting plate 21 and the UAV 1 body. When the striking mechanism 3 generates a downward striking force, its reaction force is transmitted through this rigid platform and is offset by the continuous lift provided by the rotor of the UAV 1 and the supporting force of the telescopic legs, preventing the UAV 1 body from shaking or shifting position.

[0019] The telescopic legs 22 are configured with at least three, each telescopic leg 22 including an electric telescopic rod 223 and a foot pad 224 at its end; the electric telescopic rod 223 can be driven by a motor or a linear motor to achieve precise linear extension and retraction; the foot pad 224 can be made of flexible anti-slip material such as rubber to increase friction with the concrete base plate surface and prevent slippage; the pressure sensor 221 is preferably set at the connection between the electric telescopic rod 223 and the foot pad 224 to directly measure the normal pressure when the foot pad contacts the base plate; by setting at least three support points, a plane can be stably defined to ensure the stability of the working platform.

[0020] The striking mechanism 3 is mounted on the mounting plate 21 via a bracket 31 and is used to mechanically strike the base plate to generate stress waves. The striking mechanism 3 includes a guide 32, a striking block 33, and an electromagnetic drive unit 34. The guide 32 is fixedly mounted on the bracket 31, and its axis is set to be perpendicular to the plane of the mounting plate 21, thereby ensuring that the striking direction is always perpendicular to the surface of the base plate. The striking block 33 is slidably connected to the guide 32 and can move along the axial direction of the guide. The end of the guide 32 is provided with a limiting block 321 corresponding to the striking block 33, which is used to limit the upward stroke of the striking block 33 and prevent it from falling out. The striking block 33 is made of a magnetically conductive material such as iron or low-carbon steel. The electromagnetic drive unit 34 is connected to the guide 32. The striking block 33 is coaxially positioned on the side away from the limiting block 321. When the electromagnetic drive unit 34 is energized, it generates a magnetic field that attracts the magnetically conductive striking block 33 to accelerate upward, thereby transmitting the impact to the base plate. After the power is turned off, the magnetic field disappears, and the striking block 33 falls along the guide 32 under the action of gravity, returning to its initial position. By controlling the current magnitude and on / off time of the electromagnetic drive unit 34, the lifting height and speed of the striking block 33 can be precisely controlled, thereby achieving standardization and adjustability of striking force and frequency. This provides a reliable and consistent excitation source for the quantitative analysis of sound wave signals, and the striking action is fast, accurate, and repeatable, avoiding the complex transmission and large volume caused by traditional pneumatic or mechanical impact.

[0021] The sound wave acquisition mechanism 4 is used to acquire pure impact sound wave signals when an impact occurs. It includes a soundproof enclosure 41, a sound acquisition device 42, an inflatable sealing ring 43, and an air pump 44. One end of the soundproof enclosure 41 is connected to the outer periphery of the bracket 31 of the impact mechanism 3 and sealed, while the other end has an opening facing the base plate surface. The sound acquisition device 42 can be a microphone and is installed on the inner wall of the soundproof enclosure 41. The inflatable sealing ring 43 is located at the edge of the opening end of the soundproof enclosure 41, and the air pump 44 is connected to the sealing ring 43 through an air pipe. During the test, the air pump 44 inflates the sealing ring 43, causing it to expand and fit tightly against the base plate surface, forming a temporary sealed acoustic space. This space can isolate the vibration of the UAV's own motor, the wind noise generated by the rotor, and the intrusion of external environmental noise, thereby improving the signal-to-noise ratio of the acquired sound wave signal.

[0022] To further enhance the sound insulation effect, the soundproof cover 41 can be designed as a double-layer structure, with sound-absorbing materials, such as polyurethane foam, glass wool and other porous materials, filling the interlayer. This can effectively absorb and attenuate noise that passes through the outer cover. In addition, the soundproof cover 41 is preferably made of wave-transparent materials, such as ABS resin, polycarbonate, epoxy resin, etc., which will not hinder the propagation of sound waves in the acquisition space, and can avoid the distortion of sound wave signals caused by material reflection, ensuring that the signal acquired by the sound acquisition device 42 truly reflects the vibration characteristics of the base plate.

[0023] At least two sound acquisition units 42 are evenly distributed along the inner wall of the soundproof enclosure 41. Multiple acquisition units can acquire sound wave signals from different angles. The data fusion algorithm reduces the error of a single acquisition point and improves the accuracy of feature extraction. The installation height of the acquisition units can be set in the upper middle part of the inner wall of the soundproof enclosure 41, close to the impact point, to reduce the attenuation of the sound wave propagation path. At the same time, the even distribution along the circumference can ensure that the distance between each acquisition unit and the impact point is basically the same, avoiding excessive signal time difference due to path differences.

[0024] The wall thickness of the sealing ring 43 on the side closer to the soundproof cover 41 is greater than that on the side farther away. When the sealing ring 43 is inflated, the thicker wall closer to the side has greater rigidity, while the thinner wall farther away has greater expansion. This naturally creates a deformation tendency towards the central axis of the soundproof cover 41. This ensures that the edge of the sealing ring 43 is pressed more preferentially and more tightly against the surface of the base plate, forming a more effective annular sealing band. This maximizes the prevention of sound leakage from the contact surface and ensures the purity of the sound field inside the soundproof cover 41.

[0025] To achieve rapid inflation and deflation control of the sealing ring 43, the acoustic wave acquisition mechanism 4 also includes a deflation valve 45. The deflation valve 45 is located on the inflation chamber of the sealing ring 43 and can be a solenoid valve, controlled by the drone controller 1. When the device needs to be retracted, the controller opens the deflation valve 45, and the gas in the sealing ring 43 is quickly discharged, causing it to quickly contract and detach from the base plate without affecting the movement of the drone and the operation of the next detection point.

[0026] To accurately control the inflation pressure of the sealing ring 43 and avoid damage from overpressure or poor sealing due to underpressure, the sound wave acquisition mechanism 4 also includes a pressure sensor 46. The pressure sensor 46 can be installed inside the inflation chamber of the sealing ring 43 or in the air line connecting the air pump 44 and the sealing ring 43. The pressure sensor 46 feeds back the real-time pressure signal to the controller, which then controls the start and stop of the air pump 44 accordingly. This ensures that the sealing ring 43 is maintained within a preset optimal working pressure range, guaranteeing the stability of the sound insulation and sealing effect.

[0027] It should be noted that the above embodiments are only used to illustrate the technical solution of this utility model and are not intended to limit it. Although this utility model has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solution of this utility model without departing from the spirit and scope of the technical solution of this utility model, and all such modifications or substitutions should be covered within the scope of the claims of this utility model.

Claims

1. An intelligent automatic detection device for the thickness of hollow slab bottom plate, characterized in that, It includes a drone (1), a stabilizing mechanism (2), a striking mechanism (3) and a sound wave acquisition mechanism (4), wherein the stabilizing mechanism (2), the striking mechanism (3) and the sound wave acquisition mechanism (4) are all connected to the controller of the drone (1); The stabilizing mechanism (2) includes a mounting plate (21) and multiple telescopic legs (22). The mounting plate (21) is connected to the top of the UAV (1). The multiple telescopic legs (22) are symmetrically arranged on the mounting plate (21). Pressure sensors (221) and distance sensors (222) are provided on the telescopic legs (22). The telescopic legs (22) can contact the base plate to form a stable working platform to counteract the impact reaction force. The striking mechanism (3) is mounted on the mounting plate (21) via a bracket (31) and is used to mechanically strike the base plate; The sound wave acquisition mechanism (4) includes a soundproof cover (41), a sound collector (42), an inflatable sealing ring (43), and an air pump (44). One end of the soundproof cover (41) is surrounded and sealed to the outside of the bracket (31), and the other end has an opening. The sound collector (42) is installed on the inner wall of the soundproof cover (41). The sealing ring (43) is located at the edge of the opening end of the soundproof cover (41). The air pump (44) is connected to the sealing ring (43), which allows the sealing ring (43) to expand and form a seal with the surface of the base plate during detection.

2. The intelligent automatic detection equipment for the thickness of the hollow slab bottom plate as described in claim 1, characterized in that, The telescopic legs (22) are configured to be at least three, each of the telescopic legs (22) including an electric telescopic rod (223) and a foot pad (224) at its end, and the pressure sensor (221) is disposed between the electric telescopic rod (223) and the foot pad (224).

3. The intelligent automatic detection equipment for the thickness of hollow slab bottom plate as described in claim 1, characterized in that, The striking mechanism (3) includes a guide (32), a striking block (33), and an electromagnetic drive unit (34); the guide (32) is mounted on the bracket (31), and its axis is perpendicular to the plane of the mounting plate (21); the striking block (33) is slidably connected to the guide (32), and the end of the guide (32) is provided with a limiting block (321) corresponding to the striking block (33); the striking block (33) is made of magnetic material, and the electromagnetic drive unit (34) is coaxially arranged with the guide (32) and located on the side of the striking block (33) away from the limiting block (321), for driving the striking block (33) to move along the guide (32).

4. The intelligent automatic detection equipment for the thickness of hollow slab bottom plate as described in claim 1, characterized in that, The soundproof cover (41) has a double-layer structure, with sound-absorbing material filling the interlayer; and / or, the soundproof cover (41) is made of wave-transparent material.

5. The intelligent automatic detection equipment for the thickness of hollow slab bottom plate as described in claim 1, characterized in that, At least two sound collectors (42) are evenly distributed along the inner circumference of the soundproof cover (41).

6. The intelligent automatic detection equipment for the thickness of the hollow slab bottom plate as described in claim 1, characterized in that, The wall thickness of the sealing ring (43) on the inner side near the soundproof cover (41) is greater than the wall thickness on the side away from it.

7. The intelligent automatic detection equipment for the thickness of hollow slab bottom plate as described in claim 1, characterized in that, The acoustic wave acquisition mechanism (4) also includes a vent valve (45), which is located on the inflation chamber of the sealing ring (43).

8. The intelligent automatic detection equipment for the thickness of hollow slab bottom plate as described in claim 1, characterized in that, The acoustic wave acquisition mechanism (4) also includes a pressure sensor (46), which is located in the inflation chamber of the sealing ring (43) or in the air path connecting the air pump (44) and the sealing ring (43).

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