• Title/Summary/Keyword: contact problem

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A Case Study on the Local Culture Festival in the Contact-free Era (비대면 시대의 지역문화축제 사례연구)

  • Ahn, Hyeryung;Kim, Kenneth Chi Ho
    • Journal of Digital Convergence
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    • v.19 no.11
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    • pp.425-438
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    • 2021
  • The purpose of this study is to analyze local cultural festivals hosted contact-free in the corona era and to suggest the direction for sustainable festivals in the post-corona era. To this end, by analyzing the cases of well-known festivals held contact-free in 2020 and 2021, we tried to get implications for the festivals in the post-corona era from there. As a result of this study, contact-free festivals had the following characteristics. First, the on-tact method, which produces and transmits a video or allows interaction through real-time participation, was prominent. Second, in order to compensate for the shortcomings of the contact-free method, various efforts have been made to enable on-tact experience by making and delivering experience kits in the case of experiential elements of the festival in advance. Third, communication was secured through real-time comments, and fourth, products were sold through the Internet and live commerce channels, and a certain effect was obtained. In particular, in the case of online festivals, there is a problem of loss of the sense of place of the festival, but there are cases of online festivals with more participation than offline festivals. It is judged that the problem of how to achieve this will become a reference material for the future development of contact-free festival contents.

Force-Reflecting Teleoperation for Grinding Work

  • Choo, Jung-Hoon;Lee, Jae-Yong;Lee, Jae-Won
    • 제어로봇시스템학회:학술대회논문집
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    • 2003.10a
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    • pp.824-828
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    • 2003
  • This paper explains problems of force-reflecting teleoperation grinding work and proposes some methods to solve those. For stable contact between robot tool(grindstone) and contact surface the mechanical impedance force control is used. The sliding phenomenon of grindstone has been appeared at the contact surface during the grinding work. The sliding problems caused by friction and rotation of grindstone are eliminated by using tangential direction sliding compensation control. The rotation force of grindstone makes the tool move to tangential direction along the surface suddenly even though an operator pushes the tool only in normal direction to the surface. Normal direction force control is applied for grinder not to roll and fracture on the grinding surface. Vibration problem of grindstone is decreased by second order low-pass filter. Therefore we can precise grinding work at the grinding surface and feel the reality

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An Analytic Study on the Bond Stress between Concrete and Steel Tube in CFT Rectangular Column (충전각형강관기둥에서 콘크리트와 강관의 부착응력에 관한 해석적 연구)

  • Park, Sung-Moo;Kang, Joo-Won;Kim, Won-Ho;Lee, Hyung-Seok
    • Journal of Korean Association for Spatial Structures
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    • v.2 no.4 s.6
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    • pp.53-60
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    • 2002
  • An analytic study on the bond stress between steel tube and concrete in concrete filled steel(CFT) rectangular column is presented in this paper. Recently buildings need members which are enhanced durability and ductility. Concrete filled rectangular column system is proposed as alternative plan. In this paper, ABAQUS/Standard Version 5.8 which is identified as usefulness for finite element analysis and has various element library is used. The variables in this study are the location and type of shear-connector. The modeling on contact problem practiced by Contact Pair and Contact Pressure method. In the step of physical bond, it is practiced by Change friction option After yielding of models, analytic results is less than that of experimental results.

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Relative Measurement of Differential Electrode Impedance for Contact Monitoring in a Biopotential Amplifier

  • Yoo, Sun-K.
    • International Journal of Control, Automation, and Systems
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    • v.5 no.5
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    • pp.601-605
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    • 2007
  • In this paper, we propose a simple and relative electrode contact monitoring method. By exploiting the power line interference, which is regarded as one of the worst noise sources for bio-potential measurement, the relative difference in electrode impedance can be measured without a current or voltage source. Substantial benefits, including no extra circuit components, no degradation of the body potential driving circuit, and no electrical safety problem, can be achieved using this method. Furthermore, this method can be applied to multi-channel isolated bio-potential measurement systems and home health care devices under a steady measuring environment.

Impact Force Roconstruction and Impact Model Identification Using Inverse Dynamics of an Impacted Beam (역동역학을 이용한 충격을 받는 보의 충격력 복원 및 충격모델의 변수 파악)

  • 박형순;박윤식
    • Transactions of the Korean Society of Mechanical Engineers
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    • v.19 no.3
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    • pp.623-630
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    • 1995
  • The impulse response functions (force-strain relations) for Euler-Bernoulli and Timoshenko beams are considered. The response of a beam to a transverse impact force is numerically obtained with the convolution approach using the impulse response function obtained by Laplace transform. Using this relation, the impact force history is determined in the time domain and results are compared with those from Hertz's contact law. The parameters of timpact force model are identified using the recovered force and compared with the Hertz's contact model. In order to verify the proposed algorithm, measurements were done using an impact hammer and a steel ball drop test and these results are also compared with the simulated values.

A Need of Buffering Function for Full-Off Fitting on Movable Bracket using Conventional Line (기존선 가동브래킷 곡선 당김 금구의 완충기능 필요성)

  • Ahn, Young-Hoon;Kim, Chul-Su;Lee, Seung-Il
    • Proceedings of the KSR Conference
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    • 2007.05a
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    • pp.219-222
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    • 2007
  • The Full-Off Fitting of Movable Bracket using conventional line have received a dynamic contact impact between contact wire and pantograph of electric rolling stock, so this impact cause a rapid vibration of foreword and back near the supporting point of movable bracket. The Full-Off Fitting on Movable Bracket in conventional line differs from that in high speed line. Now conventional line have required a speed up for new electric locomotive and electric car. In speed-up track and big impact place, the Full-Off Fitting and the dropper often get demage. We have done a study of buffering function to solve that problem in conventional line. We have find a need adopting buffer fitting. It is decrease a dynamic impact between contact wire and pantograph of electric rolling stock.

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A Study on the Wearing Phenomenon Analysis of Phatograph Slider for the Subway Cars (전동차 판토그라프 주습판 마모현상 분석에 관한 연구)

  • Kim, Young-Gyu;Yang, Yong-Joon;Won, Si-Tae;Choi, Kyung-Jin
    • Proceedings of the KSR Conference
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    • 2007.05a
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    • pp.208-213
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    • 2007
  • Pantograph is set on the roof of Subway. This plays the role of staying proper current on Subway when Subway is running or not. Pantograph includes Slider. Slider is most important part of Pantograph because this part is used to receive current from Contact Wire by dynamic interaction with Contact Wire. In general, material of Slider is steel, copper, or carbon alloy. Especially, SEOUL METRO uses Slider of sintered cualloy, but there is problem. This Slider causes over wearing during rainy season. We should reduce wearing between Contact Wire and Slider. Reducing this wear is most valuable technology in Subway system. I performed experiments to find out the best way that reduces the wear. I can find the best way as I change the rate of the alloy.

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Robust Hybrid Position/Force Control of a PUMA-Like Robot Manipulator (PUMA형 로보트 머니플레이터의 강인한 위치/힘 혼합제어)

  • Park, Jae-Wook;Lee, Gun-Bok
    • Proceedings of the KIEE Conference
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    • 1995.11a
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    • pp.575-578
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    • 1995
  • In general, the control of robot manipulator is classified into position control and force control. Position controllers give adequate performance when a manipulator is following a trajectory through space and end-effector has no contact with environment. However for most tasks performed by robot manipulator in industry, contact is made between the end-effector and manipulator's environment, so position control may not suffice. The objective of this study is to control both position of a manipulator and the contact forces generated at the hand by using a conceptually simple control law. Position and force control problem is decoupled into subtasts via taskspace formulation and inverse dynamics. Then, the position controllers are designed for the task space variable which represent tangent motion and the forte controllers are designed for the lash space variables which represent normal force.

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A Numerical Study on Temperature Fields in MCCB (MCCB 내의 온도장에 대한 수치적 연구)

  • Park, S.K.;Lee, Jong-Chul;Kim, Youn-J.
    • Proceedings of the KSME Conference
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    • 2003.11a
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    • pp.145-150
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    • 2003
  • In this paper we have studied the characteristics of temperature fields in a Molded Case Circuit Breaker (MCCB). A switch and a trip device are arranged in narrow space of the MCCB. Thus, thermal factors have been risen to important problem. The temperature rise means an energy loss and it becomes the reason of fatal fault in devices. Also, the temperature rise on the connection and the contact parts is regulated up to $115^{\circ}C$ and $105^{\circ}C$, respectively. Therefore, a study for preventing the temperature rise should be investigated. A numerical analysis method that has confidence might be preceded for this purpose. In order to verify the confidence of temperature field analysis, the results of the numerical analysis are compared with those of experimental one for the same model. Comparison results show a qualitatively good agreement within ${\pm}5%$ errors.

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Development of a noncontact optical sensor for measuring the shape of transparent plates (평판 투명 물체의 형상측정을 위한 비접촉식 광센서 개발)

  • 윤상필;유영기
    • 제어로봇시스템학회:학술대회논문집
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    • 2000.10a
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    • pp.214-214
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    • 2000
  • This paper deals with the non contact optical sensor to measure the shape of transparent plates such as glass panel of LCD(Liquid Crystal Display). The conventional methods to obtain the shape or thickness of a transparent plates are contact type sensor such as LVOT(Linear Variable Differential Transformer). Due to the contact between the tip of the sensor and the surface of objects, the tip is abraded. In addition, the high temperature glass casting makes the size of sensor body changed. These reasons makes the sensor degraded. In this paper, to overcome these problem, we proposed a low cost noncontact optical sensor this is composed of the Hologram laser unit of a CD-Pickup and a plastic lens. To evaluate the performance of the proposed optical sensor, a series of experiments were performed for various measurement condition. Based upon observation of the experimental result, the developed sensor shows good result for measuring the shape of transparent plates.

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