KR100359386B1 - Method and Apparatus for Inspecting Bridge Structure using Vision System - Google Patents

Abstract

The present invention provides a method and an apparatus for inspecting a defect in a lower portion of a bridge top plate for maintenance of a bridge, comprising: installing an inspection vehicle for a bridge equipped with a hydraulically operated four-section link unit on an outer side of a bridge to be examined; Attach a biaxial scalar robot at the end of the linkage section; Attaching a controllable camera vertically and horizontally on a two-axis scalar robot; Control the link section and the 2-axis scalar robot by wire or wirelessly on the bridge; As the bridge inspection car moves, the camera captures an image of a desired point and transmits it by wire or wirelessly; After the image data is processed using a vision system to determine the width and length of the cracks, and to store them in the form of a file and an apparatus therefor, according to the present invention by installing a scaffold in the human body Compared with the method of inspecting the defects of bridges, it is an excellent method for inspecting defects of bridges in terms of securing safety, objectifying survey data, and reducing labor costs.

Description

Method and device for defect inspection of bridge using vision system {Method and Apparatus for Inspecting Bridge Structure using Vision System}

The present invention relates to a method and apparatus for inspecting the external appearance of a bridge undercarriage, which involves a lot of cost and risk in visual inspection. By operating the link mechanism acting on the upper part of the bridge to approach the lower part of the bridge, control the desired position while moving the two-axis scalar robot and the inspection car, perform real-time monitoring by wire or wireless, and process the captured image by vision system The present invention relates to a method and an apparatus for performing an external investigation.

The present invention relates to a method and apparatus for economically and efficiently performing an external inspection of a substructure of a bridge where periodic visual inspection is difficult when performing an external inspection for diagnosing aging of a large structure such as a bridge.

Industrial infrastructures, such as bridges, are regularly inspected and diagnosed to ensure safety, and primarily inspect the structure for cracks and corrosion depending on appearance.

Existing test method is to install a work platform such as scaffold (3) in the lower part of the bridge through which water flows as shown in FIG. 1, and the worker (2) examines the corrosion and crack state of the bridge, To install a workbench such as the scaffolding (3) is a lot of expenses and if the wind is blowing a lot of workbench has a disadvantage that the safety of the worker is not secured. In addition, there is a method of putting the worker on the ladder and inspecting the lower part of the bridge by using the recently introduced articulated ladder truck as shown in FIG. 2, but because of the large size of the articulated ladder vehicle, traffic flow is disturbed due to lane control during work, The acquisition of objective data is a problem.

The present invention devised to solve the above problems is to install the inspection vehicle for the bridge equipped with a four-section link portion on the outside of the bridge and the desired point by the installation of a two-axis scalar robot at the end of the four-section link portion and the camera attached to the robot tip The purpose of the present invention is to provide a method and apparatus for economically and efficiently performing the visual inspection of the undercarriage of bridges by capturing the images and calculating the width and length of cracks accurately.

1-an exemplary view of a bridge inspection method according to the prior art

2-An illustration of the articulated ladder truck applied to the cable-stayed bridge or suspension bridge

3-an exemplary view of a test method according to the present invention

Fig. 4-Outline drawing of the inspection vehicle

5-Exemplary diagram of a two-axis scalar robot equipped with a zoom camera

Figure 6-Conceptual view of crack recognition by vision system

7-Example screen for crack inspection program according to the present invention

<Description of the symbols for the main parts of the drawings>

1: bridge deck 2: worker

3: scaffold 4: refraction

5: Cable 6: 1-stage link

7: 2 speed link 8: 3 speed link

9: 4-stage link 10: 2-axis scalar robot

11: camera zoom system 12: onboard vehicle

13: auxiliary frame 14: turntable

15: Section 4 Link Part 16: 1-axis Motor (for linear feed)

17: 2-axis motor (for rotation feed) 18: Camera mounting part

19: fan drive unit 20: tilt drive unit

21: high magnification zoom lens

In order to achieve the above object, the present invention sets up the inspection car on the shoulder side of the bridge as shown in FIG. 3 and controls the hydraulic link mechanism and the two-axis scalar robot to approach the camera at a desired position under the bridge. A pan drive and a tilt drive are installed on the 2-axis scalar robot to control the up, down, left and right rotation, and transmit the state of the lower part of the bridge as an image by wire or wirelessly. Visual inspection is performed by image processing using vision program.

The test apparatus used in the present invention is a two-axis scalar robot 10 equipped with a four-section link unit 6, 7, 8, 9 and a camera zoom system 11 as a moving device as shown in FIG. It consists of a video and a control wired or wireless transmission and reception module, and a vision program is used to process the received video.

The on-vehicle vehicle 12 includes an auxiliary frame 13 supporting the vehicle body and the jack, a turntable 14 supporting the four-section link unit, a four-section link unit 15 for access to the inspection site, and each driving unit as shown in FIG. 4. There is an unillustrated wired or wireless control device that can be operated, which is composed of an emergency stop device and an automatic roll over detection device as a safety device and is moved in the throttle direction.

Section 4 link portion 15 is composed of the articulated link and the boom (Boom) that can bend, pull in and withdraw as shown in Figure 3 using a high-strength steel sheet allows a wider working range with high strength and light weight It is supposed to. Section 4 operation of link part enables smooth operation and free speed control by proportional control valve and adopts wired or wireless operation method.

The 2-axis scalar robot 10 is basically driven by a 1-axis motor 16 for linear transfer and a 2-axis motor 17 for rotational transfer as shown in FIG. 5, and the control method is wired or wireless. Operators can use the remote control on site to quickly move the camera to the exact location they want and save time.

The camera zoom system 11 employs a high magnification zoom lens 21 as shown in FIG. 5, and can rotate left and right 360 degrees and up and down 90 degrees by using the pan driver 19 and the tilt driver 20. Inspection is possible.

In addition, the camera zoom system 11 has an image transmitting / receiving circuit, and transmits the captured image to a computer used as a monitoring device by wire or wirelessly, and the transmitted image is processed by the vision program of FIG. The width and length of the cracks are calculated and the image data is stored in the computer as video or image file for later analysis and comparison.

7 shows an example of analyzing a defect of a bridge using the apparatus of the present invention. In the present invention, it is important to accurately estimate the length and width of the crack because the length of the device is increased by using the inspection car and the link part, and in particular, a lot of noise may be included in the video signal of the camera due to the vibration of the bridge. To do this, one pixel size of image data should be determined. This is by applying a sensor such as an encoder or a potentiometer to a DC motor that drives the camera's zoom and focus-related lenses, and transmits the outputs of the two sensors to the controller. It can be used to automatically determine the size of a unit pixel in a program and estimate the width and length of cracks accordingly.

In the case of investigating defects in the lower part of the bridge by using the conventional method, an operator must install a work platform such as a scaffold and inspect or use a refraction ladder in the lower part of the bridge where water flows. It takes time, and in case of articulated ladder car, its size is large, which hinders the flow of cars due to lane control and is not effective in terms of work efficiency and worker safety. In addition, the conventional method evaluates the width and length of cracks based on the operator's naked eye, which not only lowers the reliability of the survey results but also gives the contradictions that the evaluation results do not coincide with each worker. In the present invention, the operator performs the real-time monitoring while adjusting the control device in the upper part of the bridge, thereby ensuring work efficiency and safety. The size of the bridge inspection car is smaller than that of the existing articulated ladder, so it is possible to drive on the shoulder, so it is unnecessary to control the vehicle on the highway. When inspecting the appearance of the bridge, the bridge inspection car can be easily moved and installed at the site to check the lower state of the bridge. The image data of each location can be saved in the form of a file in the computer, and then image processing techniques in the field of computer vision ( By using image processing, it is possible to greatly improve reliability in quantitatively determining cracks in bridges, abnormality detection of welds, width and length of cracks, and to automate and objectify inspections and judgments. Device.

Claims (2)

Installing an inspection vehicle equipped with a four-section link unit on an outside of the bridge to be examined; A two-axis scalar robot capable of pan driving and tilt driving is attached to the end of the four-section link unit, and a motor having a zoom and focus control function is attached to the front end of the two-axis scalar robot while driving the zoom and focus lens. Attaching a camera having a potentiometer attached thereto; In the upper part of the bridge, the linkage section and the 2-axis scalar robot are controlled by wire or wirelessly. Photographing an image of a desired point while the bridge inspection vehicle moves; Transmitting the photographed video signal by wire or wirelessly; Defect inspection method of a bridge, characterized in that formed by the step of examining the defect using a vision program built into the computer. Section 4 link unit mounted on the inspection vehicle for bridge inspection; A two-axis scalar robot capable of pan driving and tilt driving is attached to the end of the four-section link unit, and a motor having a zoom and focus control function is attached to the front end of the two-axis scalar robot while driving the zoom and focus lens. A camera with a potentiometer installed on it; A controller for controlling a four-link link unit and a two-axis scalar robot on a bridge by wire or wirelessly; Transmission means for transmitting a video signal photographed at a desired point while the bridge inspection vehicle moves; And a computer for analyzing a defect through the vision program embedded in the transmitted video signal.