• The Journal of Korea Robotics Society
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• v.7 no.2
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• pp.83-91
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• 2012

In this paper, we propose a cable climbing robot which can climb up and down the cables in the bridges. The robot mechanism consists of three parts: a wheel based driving mechanism, adhesion mechanism, and safe landing mechanism. The wheel based driving mechanism is driven by tooth clutches and motors. The adhesion mechanism plays the role of maintaining adhesion force by a combination of pantograph, ball screw, and springs even when the power is lost. The safe landing mechanism is developed for guaranteeing the safety of the robot during operations on cables. It can make the robot fall down with reduced speed by dissipating the gravitational forces. The robot mechanism is designed and manufactured for validating its effectiveness.

• Journal of the Korean Society for Nondestructive Testing
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• v.34 no.1
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• pp.60-67
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• 2014

In this study, an automated cable non-destructive testing(NDT) system was developed to monitor the steel cables that are a core component of cable-stayed bridges. The magnetic flux leakage(MFL) method, which is suitable for ferromagnetic continuum structures and has been verified in previous studies, was applied to the cable inspection. A multi-channel MFL sensor head was fabricated using hall sensors and permanent magnets. A wheel-based cable climbing robot was fabricated to improve the accessibility to the cables, and operating software was developed to monitor the MFL-based NDT research and control the climbing robot. Remote data transmission and robot control were realized by applying wireless LAN communication. Finally, the developed element techniques were integrated into an MFL-based cable NDT system, and the field applicability of this system was verified through a field test at Seohae Bridge, which is a typical cable-stayed bridge currently in operation.

• Journal of Mechanical Science and Technology
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• v.18 no.4
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• pp.573-581
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• 2004

A self-contained wall climbing robot, called MRWALLSPECT (Multi-functional Robot for WALL inSPECTion) II, is developed. It is designed for scanning external surfaces of gas or oil tanks with small curvature in order to find defects. The robot contains all the components for navigation in itself without any external tether cable. Although it takes the basic structure of the sliding body mechanism, the robot has its original characteristic features in the kinematic design with closed link mechanism, which is enabled by adopting a simple and robust gait pattern mimicking a biological system. By employing the proposed link mechanism, the number of actuators is reduced and high force-to-weight ratio is achieved. This paper describes its mechanism design and the overall features including hardware and software components. Also, the preliminary results of experiments are given for evaluating its performances.

• Journal of the Korea institute for structural maintenance and inspection
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• v.24 no.1
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• pp.74-79
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• 2020

Safety inspection of cable-supported bridge has increasingly attention as many cable-supported bridges are currently constructed/operated. Whilst cables as a main component in cable-supported bridge should be inspected regularly, traditional method (visual inspection) has limitation to check the condition of cables properly due to restricted factors. It is evidently necessary to develop cable-inspection robot to overcome this concern. In this respect, the main aim in this study is to manufacture the improved robot compared with the existing robot. The improved functions of the robot in this study were that the robot can be operated in large cable diameter (greater than 200 mm) and climbing ability of the robot increases. In addition, electro-magnetic sensor as a non-destructive method in the robot was added to detect damaged cables and performance of the sensor was evaluated in indoor and field experiments. Consequently, the robot was able to move on the cable with ~0.2m/s and to detect damaged cables using the sensor. It was also confirmed that performance of the robot in field test is similar to that in indoor test.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.21 no.3
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• pp.246-252
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• 2020

Safety accidents have been reported due to falling accumulated snow from cables of cable-supported bridges. In addition to the direct damage caused by falling snow, secondary damage, such as traffic accidents, can occur. Various methods have been proposed to prevent these accidents, but there are still problems in safety and practicality. In this study, a cable robot type was selected as one of the active methods for removing accumulated snow on cables. An attempt was made to increase the climbing ability of the robot to improve the efficiency of snow removal. In addition, the available range of cable diameter for the robot can be adjusted flexibly to be applied to cables used in the field. A high-resolution camera was also installed to check the surface condition of the cable in real time to increase the utility, and be used as a cable inspection robot. A three-axis accelerometer and a tension conversion algorithm were added to measure the tension force of cables. To verify the performance, indoor and field experiments were conducted, and future improvements for the inspection robot were proposed.

• Journal of the Computational Structural Engineering Institute of Korea
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• v.25 no.4
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• pp.287-292
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• 2012

In this study, Multi-Channel Magnetic Flux Leakage(MFL) sensor - based inspection system was applied to monitor the condition of cables. This inspection system measures magnetic flux to detect the local faults(LF) of steel cable. To verify the feasibility of the proposed damage detection technique, an 8-channel MFL sensor head prototype was designed and fabricated. A steel cable bunch specimen with several types of damage was fabricated and scanned by the MFL sensor head to measure the magnetic flux density of the specimen. To interpret the condition of the steel cable, magnetic flux signals were used to determine the locations of the flaws and the level of damage. Measured signals from the damaged specimen were compared with thresholds set for objective decision making. In addition, the magnetic flux density values measured from every channel were summed to focus on the detection of axial location. And, sum of flux density were displayed with threshold. Finally, the results were compared with information on actual inflicted damages to confirm the accuracy and effectiveness of the proposed cable monitoring method.