• Title/Summary/Keyword: displacement monitoring

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Six-degree-of-freedom Manipulator Displacement Measurement using Stereo Vision (스테레오비전을 이용한 6자유도 머니퓰레이터 변위 측정)

  • Lee, Dong-Hyeok;Baek, So Young;Cho, Nahm Gyoo
    • Journal of the Korean Society for Precision Engineering
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    • v.32 no.2
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    • pp.191-198
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    • 2015
  • In this paper, six-degree-of-freedom (DoF). Displacement measurement technique using a compact stereo-vision system is proposed. The measuring system consists of a camera, an optical prism, two plane mirrors, and a planar marker on a target. The target was attached on an object so that its six-DoF displacement can be calculated using a proposed coordinates estimating algorithm and stereo images of the marker. A prototype was designed and fabricated for performance test. From the test results, it can be confirmed that the proposed measuring technique can be applied to monitoring and control of various manipulators.

Development of Displacement Measuring Sensor Module to Monitoring About Variation and Distortion for Bridge Infrastructure at Wireless Communication Environmental (교량구조물의 구조적 변형을 측정하는 무선통신기반 변위센서모듈 개발)

  • Ryu, Seung-Ki;Moon, Hak-Yong
    • The Journal of The Korea Institute of Intelligent Transport Systems
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    • v.9 no.5
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    • pp.87-95
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    • 2010
  • Lots of bridge structure generated the change of outward formation according to durability capability and decrepitude by long use. Especially, in case of the typhoon, snowing and earthquake is going to make rapidly more worse formation about the old structural facilitys. Also, outward formation by irregular and micro-distortion in bridge structure could not easily checked by normal diagnostics method. As a result, performance-capability of structure facility is getting to make a decline in standard of structure performance. Recently, real-time monitoring technology by wireless environment go into the study of irregular movement for structure facility. This paper presents the development of sensor to displacement checking about bridge structure. Sensing method of developed sensor put bring into the gyroscope technology using the acceleration speed and angular acceleration speed. This paper also will simulated to verified the monitoring capability of developed sensor against random vibration, frequency and distortion in simulated equipment.

A Study on the Real Time Monitoring of Long Span Bridge Behavior Using GPS (GPS를 이용한 장대교량 실시간 거동 모니터링에 관한 연구)

  • Choi, Byoung-Gil;Sohn, Duk-Jae;Na, Young-Woo
    • Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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    • v.28 no.3
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    • pp.377-383
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    • 2010
  • This study aims to develop the system which is able to monitor long span bridge behavior in real time using GPS. Through measuring displacement of long span bridge by GPS in real time, over all 3D behavior of bridge could be analyzed and managed. Monitoring system of long span bridge which is developed in this study is able to manage in real time the safety of bridge by transmitting horizontal and vertical displacement of bridge, and danger signals to an integrated operations center. Also it is able to monitor the absolute behavior of long span bridge by GPS, and to construct a national bridge safety management networks.

Movement identification model of port container crane based on structural health monitoring system

  • Kaloop, Mosbeh R.;Sayed, Mohamed A.;Kim, Dookie;Kim, Eunsung
    • Structural Engineering and Mechanics
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    • v.50 no.1
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    • pp.105-119
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    • 2014
  • This study presents a steel container crane movement analysis and assessment based on structural health monitoring (SHM). The accelerometers are used to monitor the dynamic crane behavior and a 3-D finite element model (FEM) was designed to express the static displacement of the crane under the different load cases. The multi-input single-output nonlinear autoregressive neural network with external input (NNARX) model is used to identify the crane dynamic displacements. The FEM analysis and the identification model are used to investigate the safety and the vibration state of the crane in both time and frequency domains. Moreover, the SHM system is used based on the FEM analysis to assess the crane behavior. The analysis results indicate that: (1) the mean relative dynamic displacement can reveal the relative static movement of structures under environmental load; (2) the environmental load conditions clearly affect the crane deformations in different load cases; (3) the crane deformations are shown within the safe limits under different loads.

A Study on Efficient Design Technique of RPUM Steel Pipes (RPUM 강관의 효율적인 설계기법에 관한 연구)

  • Kim, Jung-Su;Park, Tae-Soon
    • Proceedings of the KSR Conference
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    • 2006.11b
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    • pp.1354-1363
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    • 2006
  • Until now, NATM(New Austrian Tunneling Method) has been increasingly developed based on concept of making use of ground as support. Also, NATM in its essence is a method of risk based on monitoring behaviour of tunnel. This Monitoring is irreplaceable for the quality construction of tunnel, and safety of tunnel itself. Pre-reinforcement ahead of a tunnel face using long steel pipes in NATM, known as the RPUM(Reinforced Protective Umbrella Method), is the auxiliary method to sustain the stability of a tunnel face and reduce the ground settlements. Since design of RPUM has been dependent on the empirical design, it is necessary to develop the improved design methods. In this study, to understand behaviour of steel pipes, it is monitored displacement of tunnel crown, axial force of rock bolt, displacement and axial stress of steel pipes. Also, in order to clarify the mechanical behaviour and RPUM effects, 3-Dimensional numerical analysis is performed that various cases of different parameter combinations including original length and repeated length of steel pipes, installation width and angle, repeated length of steel. In the results of comparison monitoring with analysis, it is suggested more economical and efficient design technique than empirical design methods.

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Characterizing the strain transfer on the sensing cable-soil interface based on triaxial testing

  • Wu, Guan-Zhong;Zhang, Dan;Shan, Tai-Song;Shi, Bin;Fang, Yuan-Jiang;Ren, Kang
    • Smart Structures and Systems
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    • v.30 no.1
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    • pp.63-74
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    • 2022
  • The deformation coordination between a rock/soil mass and an optical sensing cable is an important issue for accurate deformation monitoring. A stress-controlled triaxial apparatus was retrofitted by introducing an optical fiber into the soil specimen. High spatial resolution optical frequency domain reflectometry (OFDR) was used for monitoring the strain distribution along the axial direction of the specimen. The results were compared with those measured by a displacement meter. The strain measured by the optical sensing cable has a good linear relationship with the strain calculated by the displacement meter for different confining pressures, which indicates that distributed optical fiber sensing technology is feasible for soil deformation monitoring. The performance of deformation coordination between the sensing cable and the soil during unloading is higher than that during loading based on the strain transfer coefficients. Three hypothetical strain distributions of the triaxial specimen are proposed, based on which theoretical models of the strain transfer coefficients are established. It appears that the parabolic distribution of specimen strain should be more reasonable by comparison. Nevertheless, the strain transfer coefficients obtained by the theoretical models are higher than the measured coefficients. On this basis, a strain transfer model considering slippage at the interface of the sensing cable and the soil is discussed.

Visual Servoing-Based Paired Structured Light Robot System for Estimation of 6-DOF Structural Displacement (구조물의 6자유도 변위 측정을 위한 비주얼 서보잉 기반 양립형 구조 광 로봇 시스템)

  • Jeon, Hae-Min;Bang, Yu-Seok;Kim, Han-Geun;Myung, Hyun
    • Journal of Institute of Control, Robotics and Systems
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    • v.17 no.10
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    • pp.989-994
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    • 2011
  • This study aims to demonstrate the feasibility of a visual servoing-based paired structured light (SL) robot for estimating structural displacement under various external loads. The former paired SL robot, which was proposed in the previous study, was composed of two screens facing with each other, each with one or two lasers and a camera. It was found that the paired SL robot could estimate the translational and rotational displacement each in 3-DOF with high accuracy and low cost. However, the measurable range is fairly limited due to the limited screen size. In this paper, therefore, a visual servoing-based 2-DOF manipulator which controls the pose of lasers is introduced. By controlling the positions of the projected laser points to be on the screen, the proposed robot can estimate the displacement regardless of the screen size. We performed various simulations and experimental tests to verify the performance of the newly proposed robot. The results show that the proposed system overcomes the range limitation of the former system and it can be utilized to accurately estimate the structural displacement.

Targetless displacement measurement of RSW based on monocular vision and feature matching

  • Yong-Soo Ha;Minh-Vuong Pham;Jeongki Lee;Dae-Ho Yun;Yun-Tae Kim
    • Smart Structures and Systems
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    • v.32 no.4
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    • pp.207-218
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    • 2023
  • Real-time monitoring of the behavior of reinforced soil retaining wall (RSW) is required for safety checks. In this study, a targetless displacement measurement technology (TDMT) consisting of an image registration module and a displacement calculation module was proposed to monitor the behavior of RSW, in which facing displacement and settlement typically occur. Laboratory and field experiments were conducted to compare the measuring performance of natural target (NT) with the performance of artificial target (AT). Feature count- and location-based performance metrics and displacement calculation performance were analyzed to determine their correlations. The results of laboratory and field experiments showed that the feature location-based performance metric was more relevant to the displacement calculation performance than the feature count-based performance metric. The mean relative errors of the TDMT were less than 1.69 % and 5.50 % for the laboratory and field experiments, respectively. The proposed TDMT can accurately monitor the behavior of RSW for real-time safety checks.

Development of a Convergence Monitoring Method for Cylindrical Structures by Optical Fiber Bragg Grating Sensor (광섬유 FBG센서를 이용한 원주형 구조물의 2차원 상대변위 모니터링기법 개발)

  • Lho, Byeong-Cheol;Kim , Jong-Woo;Kang , Suck-Hwa
    • Journal of the Korea institute for structural maintenance and inspection
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    • v.10 no.4
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    • pp.160-166
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    • 2006
  • Optical Fiber Bragg Grating sensor has a good performance to measure microscopic displacement which can measure strain of lining concrete and cylindrical structure like high intensity containment building and it can present many advantages like a corrosion resistance from the durability point of view. Then it can measure plane geometrical displacement of cylindrical structures with two-way displacement FBG sensor module. According to the test result, measurement of FBG sensor is better performance than other electric sensor system and 2D-level measurement. As a test result, Resolution of the two-way displacement sensor module with FBG sensors are more 10 times than other LVDT or 2D surveying.