• Title/Summary/Keyword: Traverse 속도

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Position and load-swing control of a 2-dimensional overhead crane (2차원 천정크레인의 위치 및 이송물의 흔들림제어)

  • Lee, Ho-Hoon;Cho, Sung-Kun
    • Transactions of the Korean Society of Mechanical Engineers A
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    • v.21 no.10
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    • pp.1683-1693
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    • 1997
  • In this paper, a new nonlinear dynamic model is derived for a 2-dimensional overhead crane based on a new definition of 2-degree-of-freedom swing angle, and a new anti-swing control law is proposed for the crane. The dynamic model and control law take simultaneous travel and traverse motions of the crane into consideration. The model is first linearized for small motions of the crane load about the vertical stable equilibrium. Then the model becomes decoupled and symmetric with respect to the travel and traverse axes of the crane. From this result, a decoupled anti-swing control law is proposed based on the linearized model via the loop shaping and root locus methods. This decoupled method guarantees not only fast damping of load-swing but also zero steady state position error with optimal transient response for the 2-dimensional motion of the crane. Finally, the proposed control method is evaluated by controlling the simultaneous travel and traverse motions of a 2-dimensional prototype overhead crane. The effectiveness of the proposed control method is then proven by the experimental results.

Cutting Characteristics of Workpiece Using Abrasive Water-Jet Machining (Abrasive Water-Jet 가공에서 공작물의 절단특성)

  • 장현석;하만경;곽재섭;박후명;이상진;이기백
    • Proceedings of the Korean Society of Precision Engineering Conference
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    • 2002.05a
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    • pp.984-987
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    • 2002
  • Abrasive water-jet(AWJ) machining is a new cutting technology. The AWJ can cut various materials such as metal, glass and stone. However, the AWJ machining makes troubles including kerf, rounding and side taper. In this study, we investigated the correlation between parameters of abrasive water-jet machining and cutting characteristics. The machining parameters were the material thickness and the traverse speed. The experiment was conducted to cut the stainless steel(STS41) and the mild steel(SS41) specimens. The results of the experiment were presented as the relation between cutting conditions and troubles of a dimension error, a conner error, an uncut width and a kerf.

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Experimental Investigation of the flow around an Oscillating Circular Cylinder by Using a PIV System (진동하는 원형주상체 주위의 유동에 관한 PIV를 이용한 실험적 연구)

  • Song Museok;Lee Sang-Dae
    • Journal of the Korean Society for Marine Environment & Energy
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    • v.6 no.1
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    • pp.60-67
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    • 2003
  • Flow around an oscillating circular cylinder was experimentally investigated. With varying Keulegen-Carpenter(KC) number from 10 to 30 the flow field with vortex sheddings and the related hydrodynamic fortes exerting on the cylinder were measured. A newly developed PW(paricle image velocimetry) successfully captured the complex vortical flows varying with the KC number and the flow patterns were 'traverse street', 'single pairing' and 'double pairing' of vortices with increasing KC number, At a certain KC number range the lift force undergoes a transition showing little periodicity due to surrounding complicated shedded vortices.

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Mobile Robot Initial Velocity Estimation in Passive RFID Environment (수동 RFID 환경에서의 이동로봇의 초기 속도 추정)

  • Kim, Sung-Bok;Lee, Sang-Hyup;Kim, Hak-Hyun
    • Proceedings of the IEEK Conference
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    • 2008.06a
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    • pp.1053-1054
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    • 2008
  • This paper presents the mobile robot initial velocity estimation using spatial/temporal information from passive RFID system. A mobile robot is traveling along a sequence of line segments, each at a constant velocity, and the number of passive tags sensed at every sampling instant is at most one. To simplify the problem, a mobile robot is commanded to traverse two passive tags with steering angle unchanged. The 6th order polynomial equation for the mobile robot initial velocity estimation is obtained, along with some discussion on resolving the multiplicity of solutions.

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3-D Seismic Profiling (3차원 탄성파탐사)

  • Shon, Howoong
    • Economic and Environmental Geology
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    • v.29 no.6
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    • pp.739-744
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    • 1996
  • 'Kite' is a newly developed single-channel seismic imaging system capable of producing high resolution three dimensional images of subbottom geology in one traverse of a survey region. The system consists of a horizontally towed hydrophone array and active source. The hydrophone array is towed axis perpendicular to ship direction and the airgun source at the end of the hydrophone array is excited at timed intervals during the progression. The construction of the three dimensional subbottom image was made simply by using conventional multichannel seismic reflection data processing techniques. Common source shot (CSS) gathers of the hydrophone traces are evaluated using Dix's equation for average interval velocity of each subbottom layer. From the interval velocity profile and the normal consolidation stress condition, values of shear modulus, porosity, and shear velocity are deduced from the chosen values of physical constants. The system has been successfully tested at several locations on the North Atlantic continental shelf.

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Predicting Average Speed within the Enterance and Exit Ramp Junction Areas of Urban Freeway (도시고속도로의 진출·입 연결로 접속구간 내 평균속도의 추정에 관한 연구)

  • Kim, Tae Gon;Kwon, Mi Hyeon;Ji, Seung Keun
    • KSCE Journal of Civil and Environmental Engineering Research
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    • v.30 no.3D
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    • pp.215-222
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    • 2010
  • Average speed denotes a travel speed based on the average travel time of vehicles to traverse a segment of roadway, and average travel speed is used as a measure of effectiveness (MOE) suggested in the highway capacity manual (HCM) for evaluating the level of service (LOS) of roadway. Most of the urban freeways in our country are having congestion problem regardless of the rush hours as a high-speed highway with a speed limit of 80km/h or less. Especially traffic congestion within the ramp junction areas is becoming worse by the increased traffic and lack of links with the arterials around the urban freeway. So, the purpose in this study is to identify the traffic characteristics within the ramp junction areas of urban freeway, predict the average speed within the ramp junction areas based on the traffic characteristics identified, and finally prove the validity of the average speed predicted.

Efficient Localization of a Mobile Robot Using Spatial and Temporal Information from Passive RFID Environment (수동 RFID 환경에서의 공간/시간 정보를 이용한 이동로봇의 효율적 위치 추정 기법)

  • Kim, Sung-Bok;Lee, Sang-Hyup
    • Journal of the Institute of Convergence Signal Processing
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    • v.9 no.2
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    • pp.164-172
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    • 2008
  • This paper presents the efficient localization of a mobile robot traveling on the floor with tags installed, using the spatial and temporal information acquired from passive RFID environment. Compared to previous research, the proposed localization method can reduce the position estimation error and also cut down the initial cost tag installation cost. Basically, it is assumed that a mobile robot is traveling over a series of straight line segments, each at a certain constant velocity, and that the number of tags sensed by a mobile robot at each sampling instant is at most one. First, the velocity and position estimation of a mobile robot starting from a known position, which is valid for all segments except the first one. Second, for the first segment in which the starting position is unknown, the velocity and position estimation is made possible by enforcing a mobile robot to traverse at least two tags at a constant velocity with the steering angle unchanged. Third, through experiments using our passive RFID localization system, the validity and performance of the mobile robot localization proposed in this paper is demonstrated.

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The Numerical Simulation of Sediment Transport Using GIS Technique (GIS기법과 연계한 유사이송의 수치모의)

  • Han, Kun-Yeun;Lee, Eul-Rae;Choi, Hyun-Sang
    • Journal of Korean Society for Geospatial Information Science
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    • v.5 no.2 s.10
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    • pp.145-152
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    • 1997
  • A coupling of two-dimensional model and GIS technique is applied to simulate sediment transport analysis. Accurate transformations are performed for the data which have various reduced scales. Basic maps are discretized the mesh of true scale for the finite element model by using the digital map and the Traverse Mercator coordinate. Under $200m^3/s$ flow rate condition, velocity vectors, depth contours, velocity contours and deposition contours are Presented for the 5km reach of midstream of Keum River from confluence of Ji-chun to Baekche Bridge. The simulation results of the study agree well with those of one-dimensional varied flow analysis and observed data. The flow and deposition pattern revealed a meandering characteristics of the river qualitatively.

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The Generation of Directional Velocity Grid Map for Traversability Analysis of Unmanned Ground Vehicle (무인차량의 주행성분석을 위한 방향별 속도지도 생성)

  • Lee, Young-Il;Lee, Ho-Joo;Jee, Tae-Young
    • Journal of the Korea Institute of Military Science and Technology
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    • v.12 no.5
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    • pp.549-556
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    • 2009
  • One of the basic technology for implementing the autonomy of UGV(Unmanned Ground Vehicle) is a path planning algorithm using obstacle and raw terrain information which are gathered from perception sensors such as stereo camera and laser scanner. In this paper, we propose a generation method of DVGM(Directional Velocity Grid Map) which have traverse speed of UGV for the five heading directions except the rear one. The fuzzy system is designed to generate a resonable traveling speed for DVGM from current patch to the next one by using terrain slope, roughness and obstacle information extracted from raw world model data. A simulation is conducted with world model data sampled from real terrain so as to verify the performance of proposed fuzzy inference system.

Speed Enhancement Technique for Ray Casting using 2D Resampling (2차원 리샘플링에 기반한 광선추적법의 속도 향상 기법)

  • Lee, Rae-Kyoung;Ihm, In-Sung
    • Journal of KIISE:Computer Systems and Theory
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    • v.27 no.8
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    • pp.691-700
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    • 2000
  • The standard volume ray-tracing, optimized with octree, needs to repeatedly traverse hierarchical structures for each ray that often leads to redundant computations. It also employs the expensive 3D interpolation for producing high quality images. In this paper, we present a new ray-casting method that efficiently computes shaded colors and opacities at resampling points by traversing octree only once. This method traverses volume data in object-order, finds resampling points on slices incrementally, and performs resampling based on 2D interpolation. While the early ray-termination, which is one of the most effective optimization techniques, is not easily combined with object-order methods, we solved this problem using a dynamic data structure in image space. Considering that our new method is easy to implement, and need little additional memory, it will be used as very effective volume method that fills the performance gap between ray-casting and shear-warping.

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