• Title/Summary/Keyword: Position and Force Control

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Development of a dynamic sensing system for civil revolving structures and its field tests in a large revolving auditorium

  • Luo, Yaozhi;Yang, Pengcheng;Shen, Yanbin;Yu, Feng;Zhong, Zhouneng;Hong, Jiangbo
    • Smart Structures and Systems
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    • v.13 no.6
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    • pp.993-1014
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    • 2014
  • In civil engineering, revolving structures (RS) are a unique structural form applied in innovative architecture design. Such structures are able to revolve around themselves or along a certain track. However, few studies are dedicated to safety design or health monitoring of RS. In this paper, a wireless dynamic sensing system is developed for RS, and field tests toward a large revolving auditorium are conducted accordingly. At first, a wheel-rail problem is proposed: The internal force redistributes in RS, which is due to wheel-rail irregularity. Then the development of the sensing system for RS is presented. It includes system architecture, network organization, vibrating wire sensor (VWS) nodes and online remote control. To keep the sensor network identifiable during revolving, the addresses of sensor nodes are reassigned dynamically when RS position changes. At last, the system is mounted on a huge outdoor revolving auditorium. Considering the influence of the proposed problem, the RS of the auditorium has been designed conservatively. Two field tests are conducted via the sensing system. In the first test, 2000 people are invited to act as the live load. During the revolving process, data is collected from RS in three different load cases. The other test is the online monitoring for the auditorium during the official performances. In the end, the field-testing result verifies the existence of the wheel-rail problem. The result also indicates the dynamic sensing system is applicable and durable even while RS is rotating.

Study on Operation Strategy of Track-Based Curriculum for Innovative Engineering Education Industry (공학교육혁신을 위한 트랙제 교육과정 운영 방안 연구)

  • Yu, Yun Seop;Yoo, Dong-Sang
    • The Journal of Korean Institute for Practical Engineering Education
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    • v.4 no.2
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    • pp.33-37
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    • 2012
  • Hankyong National University decided to introduce a track-based curriculum for a curriculum innovation as it switched a Polytechnic University system into a general University system. A TF(task force) team was formed to study a operation strategy of a track curriculum and the opinions of campus members and educationist were gathered. Such systematic preparation was performed for the introduction of the track. Based on those works, a track-based curriculum has been operating from 2012 spring semester. A track system defines that the curriculum in a department is divided into specific majors(or tracks) and the department/agency guarantees their expertise if the students complete the course of a specific major to increase the depth and expertise in the field of study or specific areas. Track means a set of customized courses that are demanded by the corporations, and the courses include basically specific education activities, levels of education, and educational contents required for job or position of the corporation. In this paper, any issues, that arose through the operations of the track-based curriculum at Department of Electrical, Electronic and Control Engineering in Hankyong National University, and their possible solution were presented.

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A Case Study on Reinforcement of Slope in PAP Retaining Wall using Back Analysis (PAP옹벽에서 역해석을 이용한 사면보강 사례 연구)

  • Kim, Jang-Deuk;Kim, Yong-Ha
    • The Journal of Engineering Geology
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    • v.19 no.3
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    • pp.345-350
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    • 2009
  • The endpoint of the Yangbuk tunnel constructed at the national road between Gyeongju and Gampo is composed of massive cutting because the road is driven through the sides of mountain. PAP(Prestressed Anchor and PC Pannel) retaining wall as a slope stability method was established over this section. Part of the anchor in PAP wall became broken after six months. We performed inverse analysis through its measurements obtained until that time. An geological investigation to confirm the condition of ground layering and the attraction force test to find as to whether some errors might be present in the anchor were made. According to the back analysis, it was turned out that the value with soil parameter 90% that was applied to the original design was pertinent. In the redesign, the permissible stress in the anchor body was changed from 306 kN to 591 kN and 784 kN and the fixation position was increased from 11.0 m to 23.0 m. Nevertheless, five months have passed since the exchange of the anchor, the measurement results validate that stable state has been maintained. This research is considered a case that the immediate maintenance helps prevent the slope accidents.

Statistical Review for New USNCAP Side Crash Test Results (새로운 미국 측면 신차안전도평가 결과에 대한 통계적 분석)

  • Beom, Hyenkyun
    • Transactions of the Korean Society of Automotive Engineers
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    • v.21 no.2
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    • pp.104-113
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    • 2013
  • New USNCAP has been carried out by NHTSA including front and side crash from MY2011. In this paper, test results for USNCAP Side crash were reviewed by statistical analysis. This review focused on side crash test results to investigate the effect of changes from new USNCAP side crash test protocol among 30 passenger cars. These results were summarized as followings. Total number of 5 star vehicles on the front seat dummy (16 vehicles, 53.3%) was slightly smaller than the rear seat's (17 vehicles, 56.7%) in MDB test. For the ES-2re dummy, chest injury, ie maximum rib deflection contributed to 66% in the mean value of $P_{joint}$. Pelvis injury was highly dependent upon performance up to 87% in the SID-IIs dummy cited on the rear seat in average $P_{joint}$. For Pole test, pelvis injury made contribution to the average performance to 83%. For standard deviation, it showed the largest value in the same body region as the mean value for each dummy. Overall front seat performance showed 14 vehicles, 44.6% with 5 star vehicles less than each MDB or Pole test result. This result showed that performances in MDB test were different pattern to Pole test on driver position. Number of 5star vehicles for overall side NCAP performance are 18 passenger cars (60%). Curtain airbag and driver thorax airbag were equipped in all test vehicles. One vehicle is equipped with thorax airbag in the rear seat. Results from two side tests considered as reliability problem, ie the cause for large standard deviation in side crash test. Consequently, the countermeasure for new USNCAP side crash test is essential to design the effective side structures for side collision and to control well dummy kinematics with curtain and thorax airbag in order to reduce chest and pelvis injuries.

The Effects of Breathing Control on Kinetic Parameters of Lower Limbs during Walking Motion in Korean Dance (한국무용 걸음체 동작 시 호흡의 사용유무가 하지의 운동역학적 변인에 미치는 영향)

  • Park, Yang-Sun;Jang, Ji-Young
    • Korean Journal of Applied Biomechanics
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    • v.19 no.4
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    • pp.627-636
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    • 2009
  • This study aims to provide a scientific basis for the abstract beauty of dance by analyzing the effects of controlling the breath during the walking motion of Korean dance. The objective of the study is to determine the significance of breathing during Korean dance, as it is externally expressed and technologically segmented, let alone the internal beauty of Korean dance. The results of this study show that the position of the body center and ASIS during the walking motion that uses breath was lower than that of the walking motion that does not use the breath. In addition, in each replacement of the knee joint and ankle joint, a narrow angle, in which bending is used a lot, appeared during the walking motion that uses the breath, but not during the walking gesture that does not use the breath. This occurred during the bending motion. In the first peak point, the vertical ground reaction force during the walking motion that uses the breath was higher than that during the walking motion that does not use the breath.

A Study of Aesthetical Value of Composition Principle on Security Guard Martial Arts (경호무도 구성원리의 미학적 탐색)

  • Kim, Pyong-Soo;Lim, Dae-yong;Son, Jin
    • Korean Security Journal
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    • no.25
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    • pp.131-146
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    • 2010
  • Purpose of this research about reduction the scholastic systematic triangular position of the security guard martial art which repeats a development is insufficient with demand of the while society to recognize and for the philosophic value research of security guard martial art composition principle puts out with the one method and from the reporter to search the aesthetics which appears does. In order to attain the goal of the research which sees the literature which relates with an security guard martial art widly, was an investigation and observed the aesthetics from concept and martial art of aesthetics and this the technical free use ability from actual site of the technical find which leads the practice voluntary repetition practice of security guard martial art with character and the body guard aesthetic integral part experience possibly did, there being will be able to acquire an aesthetic inspiration, confirmed. So the security guard martial art follows the composition principle of maximization central attitude and shock point breath control and mental intensive etc. of reinforcement of direction shock of relativity redundancy mental moral culture body agreement characteristic force and relaxation force and is completed and will be able to embody an aesthetic value with aesthetic elements of technical polishing process inside goes about reduction.

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A Study on the Solar Panel Deployment of a Satellite (인공위성 태양전지판의 전개에 관한 연구)

  • Seo, Jong Hwi;Han, Sang Won;Park, Tae Won;Chae, Jang Su;Seo, Hyeon Seok
    • Journal of the Korean Society for Aeronautical & Space Sciences
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    • v.31 no.4
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    • pp.53-59
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    • 2003
  • Strain Energy Hinge(SEH) has been used in Korea Multi-purpose Satellite(KOMPSAT) series to deploy the solar panel due to the good record of reliability. However, when it reached a desired deployment position, a large buckling force is applied to the main body. This may cause structural damage and also affect control of the satellite. Therefore, reliable dynamic analysis for the deployment system is required at a design stage. Moreover, various mission of a satellite has made the size of solar panels got bigger, so elastic effect has to be considered seriously to get more precise analysis results. In this paper, a dynamic analysis method to predict the deployment is verified by KOMPSAT-2 deployment test.

A study on the dynamic performance of self-healing capsule based on carbonyl iron particles(CIPs) in magnetic field (자기장 환경에서 카르보닐철입자(CIPs) 기반 자가치유 캡슐의 동적 성능 분석에 관한 연구)

  • Cheng, Hao;Hu, Jie;Lim, Taeuk;Lee, Yeong Jun;Kim, Sangyou;Jung, Wonsuk
    • Proceedings of the Korean Institute of Building Construction Conference
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    • 2022.11a
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    • pp.241-242
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    • 2022
  • Recently, related studies on the application of bacterial spores to self-healing concrete have been widely reported. Using the self-healing method of bacterial spores as a kind of pro-environment, the green method is very attractive, but because the living environment of bacterial spores is relatively harsh, it is necessary to have a way to separate the living environment of bacterial spores from the harsh external environment, And release bacterial spores when needed. Therefore, capsules are widely used in self-healing concrete. To enhance the self-healing effect, the capsules need to be evenly distributed in the concrete. Furthermore, we develop a CIP-based smart capsule with controllability. We determined the magnetic force of each capsule by mixing CIP in resin, then mass-fabricating the capsules for self-healing by a microfluidic method, and by measuring the kinetic distance of the capsules containing different amounts of cip under the action of a magnetic field strength. The results show that with the increase of the amount of cip, the active distance of the capsule also increases. When the cip is 8wt%, the active distance reaches 1.75cm. We believe this research can provide momentum for the development of self-healing capsule applications.

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Interaction Analysis between Tapered Sectional Launching Nose and Superstructure Section of ILM Concrete Bridge (변단면 압출추진코와 ILM 교량 상부단면의 상호작용 해석)

  • Lee Hwan-Woo;Jung Du-Hwoe;Ahn Tae-Wook
    • Journal of the Computational Structural Engineering Institute of Korea
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    • v.19 no.2 s.72
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    • pp.139-150
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    • 2006
  • ILM(incremental launching method) bridge is one of the prestressed concrete bridge construction methods widely adopted owing to its effectiveness for the quality control. The sections of the launched superstructure pass every position of the bridge spans. This launching process causes the bridge sections to be experienced in the quite different stress states with the stress state occurred after construction completely. Due to the self weight of sections, particularly, the superstructure sections(deck) experience maximum positive and negative moment as well as maximum shear force during launching process. To minimize the temporarily caused sectional forces, launching nose is generally used in the construction method. Therefore, the magnitude of this sectional forces should be checked for the safety of super structure in construction and it is dependent on the structural characteristics of launching nose. In this study, the simplified formulas to analyze the sectional force occurred by the nose-deck interaction in ILM construction are developed. The considering parameters are the span length ratio, stiffness ratio and weight ratio between the launching nose and the super structure. In particular, the developed formulas can consider the tapered sectional shape of launching nose and the diaphragm wall in the superstructure. Additionally, the sensitivity analysis is performed to analyze the effects of nose-deck interaction according to the design parameters.

A LiDAR-based Visual Sensor System for Automatic Mooring of a Ship (선박 자동계류를 위한 LiDAR기반 시각센서 시스템 개발)

  • Kim, Jin-Man;Nam, Taek-Kun;Kim, Heon-Hui
    • Journal of the Korean Society of Marine Environment & Safety
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    • v.28 no.6
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    • pp.1036-1043
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    • 2022
  • This paper discusses about the development of a visual sensor that can be installed in an automatic mooring device to detect the berthing condition of a vessel. Despite controlling the ship's speed and confirming its location to prevent accidents while berthing a vessel, ship collision occurs at the pier every year, causing great economic and environmental damage. Therefore, it is important to develop a visual system that can quickly obtain the information on the speed and location of the vessel to ensure safety of the berthing vessel. In this study, a visual sensor was developed to observe a ship through an image while berthing, and to properly check the ship's status according to the surrounding environment. To obtain the adequacy of the visual sensor to be developed, the sensor characteristics were analyzed in terms of information provided from the existing sensors, that is, detection range, real-timeness, accuracy, and precision. Based on these analysis data, we developed a 3D visual module that can acquire information on objects in real time by conducting conceptual designs of LiDAR (Light Detection And Ranging) type 3D visual system, driving mechanism, and position and force controller for motion tilting system. Finally, performance evaluation of the control system and scan speed test were executed, and the effectiveness of the developed system was confirmed through experiments.