• Title/Summary/Keyword: component modeling

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A Local Path Planning Algorithm considering the Mobility of UGV based on the Binary Map (무인차량의 주행성능을 고려한 장애물 격자지도 기반의 지역경로계획)

  • Lee, Young-Il;Lee, Ho-Joo;Ko, Jung-Ho
    • Journal of the Korea Institute of Military Science and Technology
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    • v.13 no.2
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    • pp.171-179
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    • 2010
  • A fundamental technology of UGV(Unmanned Ground Vehicle) to perform a given mission with success in various environment is a path planning method which generates a safe and optimal path to the goal. In this paper, we suggest a local path-planning method of UGV based on the binary map using world model data which is gathered from terrain perception sensors. In specially, we present three core algorithms such as shortest path computation algorithm, path optimization algorithm and path smoothing algorithm those are used in the each composition module of LPP component. A simulation is conducted with M&S(Modeling & Simulation) system in order to verify the performance of each core algorithm and the performance of LPP component with scenarios.

Analysis and Design of DC-DC Converter with Independent Dual Outputs (독립적인 이중 출력을 갖는 DC-DC 컨버터의 해석 및 설계)

  • Heo, Tae-Won;Park, Ji-Ho;Kim, Dong-Wan;Woo, Jung-In
    • The Transactions of the Korean Institute of Electrical Engineers P
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    • v.54 no.4
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    • pp.171-178
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    • 2005
  • The proposed dual-output DC-DC converter that bases on flyback converter can obtain two output voltage with non-isolated main-output and isolated sub-output at the same time using single-winding high frequency transformer. It can solve problems in multi-winding converter that use one main-switch, and also control quality of isolated sub-output voltage can be improved by additional sub-switch to the second. For analysis and design of the proposed converter system, converters are classified as operation mode from switching state and are become modeling by applying state space averaging method. Steady-state characteristics and dynamic characteristics are analyzed by DC component and perturbation component from state space averaging model. From experiment converter, validity of analysis and design for the propose converter system is confirm.

Dynamic Modeling of Bolt Joints Using Lumped Mass-Spring Model (집중 질량-스프링 모델을 이용한 볼트 결합부 모델링)

  • Go, Gang-Ho;Lee, Jang-Mu
    • Transactions of the Korean Society of Mechanical Engineers A
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    • v.25 no.3
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    • pp.495-501
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    • 2001
  • In this paper, a new technique which models the joints characteristics through reduction of DOFs of structures with joints using component mode synthesis (CMS) method is proposed. Bolt joints are modeled by mass-spring systems. Also generalized mass and stiffness matrices for this models are introduced. Because bolt joints have influence on eigenvalues of structures, exact eigenvalues from modal test are used. The results show that the behaviors of structures with bolt joints depend to a large extent on the translational DOFs and not on rotational DOFs of mass and stiffness matrices of bolts. Furthermore it is confirmed that lumped mass-spring systems as models of bolt joints are effective models considering the facts that joint characteristics converged to constant values in some iterations and eignevalues from proposed method are in good agreement with ones from modal test.

A Study on the Simplified Controller for the Heavy-Load Traverse Driving System Using Performance Estimation Program (성능추정 프로그램을 이용한 대부하 선회구동/제어 시스템 단순화 연구)

  • Choi, Keun-Kuk;Lee, Man-Hyung
    • Journal of Institute of Control, Robotics and Systems
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    • v.6 no.4
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    • pp.261-267
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    • 2000
  • In this study, a heavy-load servo-control driving system, which are composed of controller, electro-hydraulic servomechanism, hydraulic motor, reduction gearbox, turret slew bearing and turret structure, are investigated to simplify the servo-control system. To estimate the effect of each component, nonlinear modeling and simulation are carried out. In the first stage, to prove the validity of the performance estimation program, simulation results are compared with experimental results. In the second stage, the effect of each component of the control system is evaluated and then a simplified control system is suggested.

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Study on Improved Loss Model for Incompressible Regenerative Turbomachines (비압축성 재생형 기계의 손 실 모델 개선에 관한 연구)

  • Choi, Won-Chul;Yoo, Il-Su;Chung, Myung-Kyoon
    • 한국전산유체공학회:학술대회논문집
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    • 2008.03b
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    • pp.341-344
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    • 2008
  • The complicated helical flow formed in the regenerative turbomachines is usually decomposed into a peripheral component and a circulatory component. On the basis of the momentum exchange theory, the circulatory flow plays a critical role of imparting angular momentum to the peripheral flow. Therefore, the accuracy of performance prediction is dominated by the circulatory flow modeling. Until now the circulatory flow has been accounted of a standstill flow normal to the peripheral flow. However, the circulatory path from the impeller exit to the re-entrance inlet is exposed to the adverse pressure gradient, so it would be more realistic to describe that the circulatory flow is formed on the skewed plane not perpendicular to the peripheral flow. Present study suggests new circulatory flow loss model including the effect of adverse pressure gradient and modifies the effective circulatory flow rate and circulatory pivot which were previously published.

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Indirect Adaptive Fuzzy Sliding Mode Control for Nonaffine Nonlinear Systems

  • Seo, Sam-Jun
    • International Journal of Fuzzy Logic and Intelligent Systems
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    • v.5 no.2
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    • pp.145-150
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    • 2005
  • We proposed the indirect adaptive fuzzy model based sliding mode controller to control nonaffine nonlinear systems. Takagi-Sugano fuzzy system is used to represent the nonaffine nonlinear system and then inverted to design the controller at each sampling time. Also sliding mode component is employed to eliminate the effects of disturbances, while a fuzzy model component equipped with an adaptation mechanism reduces modeling uncertainties by approximating model uncertainties. The proposed controller and adaptive laws guarantee that the closed-loop system is stable in the sense of Lyapunov and the output tracks a desired trajectory asymptotically.

Optimum Vibration Angle for Transporting Granular Materials on Linear Conveyors

  • Keraita, James Nyambega
    • International Journal of Precision Engineering and Manufacturing
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    • v.9 no.2
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    • pp.3-7
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    • 2008
  • Vibratory conveyors are widely used in industry to transport granular materials and products. A theoretical point mass model for vibratory conveying was studied. The results agreed well with experimental observations. The model theory included the resting, sliding and flight states of the material. Each state was considered separately when determining the equations of motion. For the coefficients of restitution, values of zero for the normal component and 0.8 for the tangential component were found to be appropriate for modeling the collisions of the granular particles with the conveying surface. The vibration angle had a large influence on the mode and rate of transport. There was an optimum vibration angle for a given set of conditions. The optimum vibration angle decreased and was better defined as the coefficient of friction increased. The results suggest the existence of an optimum dimensionless track acceleration (throw number), which does not support general industrial practice in which the track acceleration is limited when the feed cycle becomes erratic and unstable.

A Space-Time Model with Application to Annual Temperature Anomalies;

  • Lee, Eui-Kyoo;Moon, Myung-Sang;Gunst, Richard F.
    • Communications for Statistical Applications and Methods
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    • v.10 no.1
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    • pp.19-30
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    • 2003
  • Spatiotemporal statistical models are used for analyzing space-time data in many fields, such as environmental sciences, meteorology, geology, epidemiology, forestry, hydrology, fishery, and so on. It is well known that classical spatiotemporal process modeling requires the estimation of space-time variogram or covariance functions. In practice, the estimation of such variogram or covariance functions are computationally difficult and highly sensitive to data structures. We investigate a Bayesian hierarchical model which allows the specification of a more realistic series of conditional distributions instead of computationally difficult and less realistic joint covariance functions. The spatiotemporal model investigated in this study allows both spatial component and autoregressive temporal component. These two features overcome the inability of pure time series models to adequately predict changes in trends in individual sites.

A custom building deterioration model

  • Hosny, O.A.;Elhakeem, A.A.;Hegazy, T.
    • Structural Engineering and Mechanics
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    • v.37 no.6
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    • pp.685-691
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    • 2011
  • Developing accurate prediction models for deterioration behavior represents a challenging but essential task in comprehensive Infrastructure Management Systems. The challenge may be a result of the lack of historical data, impact of unforeseen parameters, and/or the past repair/maintenance practices. These realities contribute heavily to the noticeable variability in deterioration behavior even among similar components. This paper introduces a novel approach to predict the deterioration of any infrastructure component. The approach is general as it fits any component, however the prediction is custom for a specific item to consider the inherent impacts of expected and unexpected parameters that affect its unique deterioration behavior.

GASS Improvement using Diverse Communication Layers of Material and Information (정보 전달계의 분리를 통한 GASS의 개선)

  • Kim, Tae-Gon;Lee, Jeong-Jae
    • Journal of The Korean Society of Agricultural Engineers
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    • v.49 no.1
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    • pp.101-109
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    • 2007
  • The purpose of this study is to improve ability of GASS using diverse communication layers of material and information. GASS is a dynamic system simulator developed for analyzing complex agricultural system. However, it had two difficulties which are inefficient modeling of information transmission and complicated implementation of material transmission. This paper proposes dual communication layers which consist of material and information to overcome the hardship and applies intake tower component which controls amount of irrigation using water requirement in paddy to an irrigation system model. The application focused on available information communication and correctable material communication.