A cable testing device for cable-stayed bridges

Abstract

This utility model discloses a cable-stayed bridge cable inspection device, belonging to the technical field of bridge inspection equipment. It mainly solves the problems of unstable clamping and insufficient accuracy in curved surface inspection of existing cable inspection devices. The device includes a mobile robot, an image acquisition module, and a laser rangefinder. The image acquisition module is mounted above and below the front end of the mobile robot via a two-axis gyroscope-stabilized gimbal. The laser rangefinder is fixed to the bottom of the mobile robot, with its laser emission direction forming a 30-35° angle with the cable axis. A main controller is installed inside the mobile robot, connecting the image acquisition module and the laser rangefinder. This device is mainly used for detecting surface defects in cable-stayed bridge cables, enabling stable clamping and high-precision curved surface inspection of the cables.

Description

Technical Field

[0001] This utility model relates to the technical field of bridge inspection equipment. More specifically, this utility model relates to a cable inspection device for cable-stayed bridges. Background Technology

[0002] As the main load-bearing components, cable-stayed bridge cables are prone to surface damage due to long-term exposure to the natural environment, requiring regular inspection. Currently used inspection methods face two main technical challenges: First, there's the issue of clamping stability. Traditional inspection devices use rigid clamping mechanisms, which are prone to slippage or detachment when the cable surface is uneven or the protective layer thickness is inconsistent. This is because cables undergo diameter changes and surface irregularities over long-term use, and existing clamping mechanisms lack adaptive adjustment capabilities. Second, there's the issue of surface curvature inspection accuracy. Conventional inspection equipment uses vertically mounted devices to measure the cable surface. However, cable-stayed bridge cables are cylindrical or near-cylindrical structures with continuous curved surfaces. When the inspection equipment measures the curved surface vertically, deviations between the measuring beam or field of view axis and the local normal direction of the cable lead to errors in the obtained data, especially noticeable in small-diameter cables or sections with large surface curvature. Summary of the Invention

[0003] The purpose of this invention is to provide a cable-stayed bridge cable inspection device that ensures the stable attachment of a mobile robot during the inspection process and improves the reliability of the inspection data.

[0004] The technical solution adopted by this utility model to solve this technical problem is: a cable detection device for cable-stayed bridges, comprising: a mobile robot, an image acquisition module, and a laser rangefinder; The image acquisition module is mounted on the top and bottom of the front end of the mobile robot via a two-axis gyroscope stabilized gimbal. The laser rangefinder is fixed to the bottom of the mobile robot, and the laser emission direction of the laser rangefinder is at an angle of 30-35° with the cable axis. The mobile robot is equipped with a main controller, which is connected to an image acquisition module and a laser rangefinder.

[0005] As a further aspect of this utility model, the pitch adjustment range of the two-axis gyro stabilized gimbal is ±30 degrees, and the roll adjustment range is ±15 degrees.

[0006] As a further embodiment of this utility model, the mobile robot has a ring frame, which consists of ring skeletons at both ends and connecting rods connecting the ring skeletons at both ends; the ring skeleton is formed by two semi-circular rings that can be opened and closed by hinges and bolts. The mobile robot has two sets of symmetrically arranged walking wheels. Each set of walking wheels includes two drive wheels distributed at 180°. The surface of the drive wheels is covered with a rubber layer and driven independently by a servo motor. The main controller is connected to the servo motor.

[0007] As a further embodiment of this utility model, the drive wheel and the servo motor are connected to the connecting rod through a connecting assembly, the connecting assembly including a base and a gas spring.

[0008] As a further embodiment of this utility model, the mobile robot has two sets of auxiliary wheel sets distributed at 180°; the auxiliary wheel sets include a gas spring, an upper arc plate, an arc airbag, and a lower arc plate; The upper and lower ends of the gas spring are fixed to the connecting rod and the upper arc plate, respectively. The top and bottom surfaces of the arc-shaped airbag are fixed to the upper and lower arc plates, respectively. The inflation port of the arc-shaped airbag is connected to an external air pump through an air pipe. The main controller controls the operation of the air pump. The bottom surface of the lower arc plate is provided with auxiliary wheels.

[0009] As a further embodiment of this utility model, the auxiliary wheel set and the walking wheel set are arranged in a staggered manner along the circumference of the cable.

[0010] This utility model has at least the following beneficial effects: The cable-stayed bridge cable inspection device provided by this utility model effectively improves the stability of inspection operations and the reliability of data acquisition. Through its unique adaptive clamping mechanism, it ensures stable attachment of the mobile robot under various cable surface conditions, overcoming the technical problems of slippage and detachment inherent in traditional rigid clamping.

[0011] The device employs a non-perpendicular oblique laser measurement structure, significantly reducing measurement errors caused by surface curvature and achieving high-precision quantitative detection of cable surface morphology. Simultaneously, the image acquisition module, in conjunction with a highly stable gimbal, effectively suppresses operational vibrations, resulting in clearer and more accurate surface image data.

[0012] Other advantages, objectives and features of this invention will be partly apparent from the following description, and partly understood by those skilled in the art through study and practice of this invention. Attached Figure Description

[0013] Figure 1 This is a schematic diagram of the cable testing device for cable-stayed bridges according to this utility model; Figure 2 This is a schematic diagram from another perspective of the cable-stayed bridge cable detection device of this utility model; Figure 3 This is a schematic diagram of the auxiliary wheel assembly of this utility model; Figure 4 This is a schematic diagram of the drive wheel of this utility model.

[0014] Among them, 1-cable, 2-image acquisition module, 3-laser rangefinder, 4-ring frame, 5-connecting rod, 6-drive wheel, 7-servo motor, 8-bolt, 9-base, 10-gas spring, 11-upper arc plate, 12-arc airbag, 13-lower arc plate, 14-auxiliary wheel. Detailed Implementation

[0015] The present invention will now be described in detail and completely with reference to the accompanying drawings. Those skilled in the art will be able to implement the present invention based on these descriptions. Before describing the present invention with reference to the accompanying drawings, it should be particularly noted that the technical solutions and features provided in the various parts of the present invention, including the following description, can be combined with each other without conflict.

[0016] Furthermore, the embodiments of the present invention described below are generally only a part of the embodiments of the present invention, and not all of the embodiments. Therefore, all other embodiments obtained by those skilled in the art based on the embodiments of the present invention without inventive effort should fall within the protection scope of the present invention.

[0017] The present invention will be further described in detail below with reference to the accompanying drawings and embodiments, and the specific implementation process is as follows: like Figures 1-4 As shown, this utility model provides a cable inspection device for cable-stayed bridges, including: a mobile robot, an image acquisition module, and a laser rangefinder; The image acquisition module uses a 20-megapixel industrial camera, mounted above and below the front of the mobile robot via a two-axis gyro-stabilized gimbal. This gimbal effectively overcomes the impact of crawling jitter on image quality, ensuring accurate defect identification. This layout aims to achieve synchronous image coverage of the upper and lower semi-circular surfaces of the cable, eliminating blind spots. The laser rangefinder primarily detects stress concentration areas in the cable, located on the lower arc surface. Therefore, the laser rangefinder is rigidly fixed to the bottom of the mobile robot, with its laser emission direction forming a 30-35° angle with the cable axis. A main controller is installed inside the mobile robot, connected to the two cameras in the image acquisition module via Ethernet cables to receive high-definition image data. Simultaneously, the main controller communicates with the laser rangefinder via an RS-485 serial bus. In this embodiment, the laser rangefinder is installed at a 35° angle. This angle design causes the laser beam to form an oblique scanning trajectory on the curved surface of the cable. Compared with the vertical incidence method, this significantly reduces the measurement error on curved surfaces and solves the data distortion problem of traditional vertical measurement methods on curved surfaces. After the device is started, the mobile robot crawls along the cable. Under the stabilization of the gimbal, the upper and lower cameras continuously or at fixed intervals capture two-dimensional image data of the cable surface condition. At the same time, the laser rangefinder emits a laser beam at a high frequency. The laser beam is incident obliquely on the lower surface of the cable at a 32° angle. As the robot moves, the laser spot forms an oblique scanning trajectory on the lower surface of the cable.

[0018] In another technical solution, the pitch adjustment range of the two-axis gyro-stabilized gimbal is ±30 degrees, and the roll adjustment range is ±15 degrees.

[0019] In another technical solution, the mobile robot has a ring frame, which consists of ring skeletons at both ends and connecting rods connecting the two ring skeletons; the ring skeleton is formed by two semi-circular rings that can be opened and closed by hinges and bolts, and the connecting rods are all set to avoid the hinge joints of the semi-circular rings; The mobile robot has two symmetrically arranged sets of walking wheels. Each set of wheels includes two drive wheels distributed at 180°. The surface of the drive wheels is covered with a high-friction coefficient rubber layer and is independently driven by a servo motor. The main controller is connected to the servo motors via a CAN bus. In this embodiment, each drive wheel is driven by an independent servo motor, and all servo motors are connected to the main controller. Each servo motor's output shaft is equipped with an encoder. The main controller adjusts the speed of each servo motor in real time based on the feedback signals from each encoder, ensuring that all drive wheels rotate synchronously.

[0020] The operator loosens the bolts, opens the ring-shaped frame, places it onto the cable, and then closes and locks it. Four drive wheels, pressed against the cable surface by springs, generate positive pressure, which is then converted into static friction. The main controller sends identical speed commands to the four servo motors. The servo motors drive the drive wheels to rotate, thus propelling the entire robot along the cable. This implementation, with its openable and closable ring-shaped frame design, greatly improves the ease of deployment of the device.

[0021] In another technical solution, the drive wheel and servo motor are connected to a connecting rod via a connecting assembly, which includes a base and a gas spring. One end of the gas spring is connected to the connecting rod, and the other end is connected to the base, which is used to fix the servo motor. This connecting assembly, using a gas spring as the force-applying element, provides clamping force to the drive wheel. It offers rapid response, high reliability, and eliminates the need for complex electronic control, effectively ensuring optimal adhesion for the drive wheel under various cable conditions. It is a key mechanical structure for achieving stable clamping and efficient drive.

[0022] In another technical solution, the mobile robot has two sets of auxiliary wheel sets distributed at 180°; the auxiliary wheel sets include gas springs, upper arc-shaped plates, arc-shaped airbags, and lower arc-shaped plates; The upper and lower ends of the gas spring are fixed to the connecting rod and the upper arc plate, respectively. The top and bottom surfaces of the arc-shaped airbag are fixed to the upper and lower arc plates, respectively. The inflation port of the arc-shaped airbag is connected to an external air pump through an air pipe. The main controller controls the operation of the air pump. The bottom surface of the lower arc plate is provided with auxiliary wheels. In this embodiment, four auxiliary wheels are provided on the bottom surface of the lower arc plate, arranged symmetrically in pairs. By introducing the arc-shaped airbag and gas spring to adjust the pressure between the auxiliary wheels and the cable, and by combining the arc-shaped airbag and the lower arc plate, and by setting the upper arc plate, arc-shaped airbag, and lower arc plate to be arc-shaped with the same curvature as the cable, the number of auxiliary wheels is increased, improving the mobile robot's wrapping ability around the cable, providing stable auxiliary support, and better adapting to local concavities and bulges in the cable, ensuring the robot's stable operation and safety under various complex working conditions.

[0023] In another technical solution, the auxiliary wheel set and the walking wheel set are staggered along the circumference of the cable, which scientifically plans the spatial layout of all wheel systems on the mobile robot.

[0024] Although the embodiments of this utility model have been disclosed above, they are not limited to the applications listed in the specification and embodiments. They can be applied to various fields suitable for this utility model. For those skilled in the art, other modifications can be easily made. Therefore, without departing from the general concept defined by the claims and their equivalents, this utility model is not limited to the specific details and embodiments shown and described herein.

Claims

1. A cable detection device for a cable-stayed bridge, characterized by, include: Mobile robots, image acquisition modules, and laser rangefinders; The image acquisition module is mounted on the top and bottom of the front end of the mobile robot via a two-axis gyroscope stabilized gimbal. The laser rangefinder is fixed to the bottom of the mobile robot, and the laser emission direction of the laser rangefinder is at an angle of 30-35° with the cable axis. The mobile robot is equipped with a main controller, which is connected to an image acquisition module and a laser rangefinder.

2. The cable detection apparatus of claim 1, wherein The pitch adjustment range of the two-axis gyro-stabilized gimbal is ±30 degrees, and the roll adjustment range is ±15 degrees.

3. The cable detection apparatus of claim 1, wherein The mobile robot has a ring frame, which consists of ring skeletons at both ends and connecting rods connecting the two ring skeletons; the ring skeleton is formed by two semi-circular rings that can be opened and closed by hinges and bolts. The mobile robot has two sets of symmetrically arranged walking wheels. Each set of walking wheels includes two drive wheels distributed at 180°. The surface of the drive wheels is covered with a rubber layer and driven independently by a servo motor. The main controller is connected to the servo motor.

4. The cable detection apparatus of claim 3, wherein The drive wheel and servo motor are connected to the connecting rod via a connecting assembly, which includes a base and a gas spring.

5. The cable detection apparatus of claim 3, wherein The mobile robot has two sets of auxiliary wheels distributed at 180°; each auxiliary wheel set includes a gas spring, an upper arc plate, an arc airbag, and a lower arc plate. The upper and lower ends of the gas spring are fixed to the connecting rod and the upper arc plate, respectively. The top and bottom surfaces of the arc-shaped airbag are fixed to the upper and lower arc plates, respectively. The inflation port of the arc-shaped airbag is connected to an external air pump through an air pipe. The main controller controls the operation of the air pump. The bottom surface of the lower arc plate is provided with auxiliary wheels.

6. The cable detection apparatus of claim 5, wherein The auxiliary wheel set and the traveling wheel set are arranged in a staggered manner along the circumference of the cable.

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