• Title, Summary, Keyword: Dynamic Model

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Lateral Dynamic Model of an All-Wheel Steered Articulated Vehicle for Guidance Control (전차륜조향 굴절차량의 안내제어를 위한 횡방향 동역학 모델)

  • Yun, Kyoung-Han;Kim, Young-Chol;Min, Kyung-Deuk;Byun, Yeun-Sub
    • The Transactions of The Korean Institute of Electrical Engineers
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    • v.60 no.6
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    • pp.1229-1238
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    • 2011
  • This paper deals with the lateral dynamic model of an all-wheel steered articulated vehicle to design a guidance controller. Nonlinear dynamic model of articulated vehicle is developed by complementing the model about the BRT system of California PATH in U. S. A. and the Phileas system of the APTS in Netherlands. Linear lateral dynamic model has been derived from the nonlinear dynamic model under some assumptions associated with the driving conditions. To design a guidance controller, we derive a transfer function that is steering angle as input and lateral acceleration as output from the linear lateral dynamic model by applying the parameter of vehicle that is developed by Korea Railroad Research Institute. To validate the dynamic model, nonlinear dynamic model has been compared with a vehicle model that has been programmed in ADAMS, and linear dynamic model has been compared with a nonlinear dynamic model under sime assumptions.

A Study on increasing the fitness of forecasts using Dynamic Model (동적 모형에 의한 예측치의 정도 향상에 관한 연구)

  • 윤석환;윤상원;신용백
    • Journal of the Society of Korea Industrial and Systems Engineering
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    • v.19 no.40
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    • pp.1-14
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    • 1996
  • We develop a dynamic demand forecasting model compared to regression analysis model and AutoRegressive Integrated Moving Average(ARIMA) model. The dynamic model can apply to the current dynamic data to forecasts through introducing state equation. A multiple regression model and ARIMA model using given data are designed via the model analysis. The forecasting fitness evaluation between the designed models and the dynamic model is compared with the criterion of sum of squared error.

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An Analysis of Dynamic Cutting Force Model for Face Milling Using Modified Autoregressive Vector Model (자기회귀 벡터모델을 이용한 정면밀링의 동절삭력 모델해석)

  • 백대균;김정현;김희술
    • Transactions of the Korean Society of Mechanical Engineers
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    • v.17 no.12
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    • pp.2949-2961
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    • 1993
  • Dynamic cutting process can be represented by a closed-loop0 system consisted of machine tool structure and pure cutting process. On this paper, cutting system is modeled as a six degrees of freedom system using MARV(Modified Autoregressive Vector) model in face milling, and the modeled dynamic cutting process is used to predict dynamic cutting force component. Based on the double modulation principle, a dynamic cutting force model is developed. From the simulated relative displacements between tool and workpiece the dynamic force domponents can be calculated, and the dynamic force can be obtained by superposition of the static force and dynamic force components. The simulated dynamic cutting forces have a good agreement with the measured cutting force.

Flutter Analysis of Small Aircraft using Full Airframe Dynamic FE Model (전기체 동적 유한요소 모델을 이용한 소형항공기 플러터 해석)

  • Lee, Sang-Wook;Paek, Seung-Kil;Kim, Sung-Chan;Hwang, In-Hee
    • Proceedings of the KSME Conference
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    • pp.424-429
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    • 2008
  • Aircraft flutter analysis model consists of dynamic FE model and aerodynamic model. Dynamic FE model is composed of stiffness and mass model, and is used for the prediction of normal mode characteristics of the structure. Since aircraft flutter analysis is normally performed in the modal domain, dynamic FE model shall be constructed to describe the modal characteristics of the structure with sufficient accuracy. In this study, dynamic FE modeling method was described using full airframe FE model and structural and system weight data for aircraft flutter analysis. In addition, full airframe dynamic FE model for composite small aircraft was constituted for normal mode and flutter analysis, and the mass modeling results were compared with the target weight data to validate the mass modeling method proposed. Finally, full airframe flutter analysis of composite small aircraft was performed with the dynamic FE model and the aerodynamic model composed.

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FE model updating method incorporating damping matrices for structural dynamic modifications

  • Arora, Vikas
    • Structural Engineering and Mechanics
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    • v.52 no.2
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    • pp.261-274
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    • 2014
  • An accurate finite element (FE) model of a structure is essential for predicting reliably its dynamic characteristics. Such a model is used to predict the effects of structural modifications for dynamic design of the structure. These modifications may be imposed by design alterations for operating reasons. Most of the model updating techniques neglect damping and so these updated models can't be used for accurate prediction of vibration amplitudes. This paper deals with the basic formulation of damped finite element model updating method and its use for structural dynamic modifications. In this damped damped finite element model updating method, damping matrices are updated along with mass and stiffness matrices. The damping matrices are updated by updating the damping coefficients. A case involving actual measured data for the case of F-shaped test structure, which resembles the skeleton of a drilling machine is used to evaluate the effectiveness of damped FE model updating method for accurate prediction of the vibration levels and thus its use for structural dynamic modifications. It can be concluded from the study that damped updated FE model updating can be used for structural dynamic modifications with confidence.

A Flexible Multi-body Dynamic Model for Analyzing the Hysteretic Characteristics and the Dynamic Stress of a Taper Leaf Spring

  • Moon Il-Dong;Yoon Ho-Sang;Oh Chae-Youn
    • Journal of Mechanical Science and Technology
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    • v.20 no.10
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    • pp.1638-1645
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    • 2006
  • This paper proposes a modeling technique which is able to not only reliably and easily represent the hysteretic characteristics but also analyze the dynamic stress of a taper leaf spring. The flexible multi-body dynamic model of the taper leaf spring is developed by interfacing the finite element model and computation model of the taper leaf spring. Rigid dummy parts are attached at the places where a finite element leaf model is in contact with an adjacent one in order to apply contact model. Friction is defined in the contact model to represent the hysteretic phenomenon of the taper leaf spring. The test of the taper leaf spring is conducted for the validation of the reliability of the flexible multi-body dynamic model of the taper leaf spring developed in this paper. The test is started at an unloaded state with the excitation amplitude of $1{\sim}2mm/sec$ and frequency of 132 mm. First, the simulation is conducted with the same condition as the test. Then, the simulations are conducted with various amplitudes in a loaded state. The hysteretic diagram from the test is compared with the ones from the simulation for the validation of the reliability of the model. The dynamic stress analysis of the taper leaf spring is also conducted with the developed flexible multi-body dynamic model under a dynamic loading condition.

Implementation of a dynamic control for a mobile robot (이동 로보트의 동적 제어 구현)

  • 이장명;김용태
    • Journal of the Korean Institute of Telematics and Electronics S
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    • v.34S no.1
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    • pp.54-64
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    • 1997
  • In this paper, a method of dynamic modeling and a dynamic control of a mobile robot are presented to show the superiority of the dynamic control comparing to the PD control. This dynamic model is derived from the cartesian coordinates using lagrange equations. Based upon the derived dynamic model, we implemented the dynamic control of the mobile robot using the computed torque method. Time varying non-linear friction terms are not incroporated in this dynamic model. Instead, those are considered as disturbances. This uncertainty in dynamic model of mobile robot is compensated by the outer loop controller using PD algorithm. The validity of this model and the control algorithm are confirmed through the experiments, where the dynamic control algorithm demonstrated robust velocity tracking performance against the unmodeled non-linear frictions. The superiority of this algorithm is demonstrated by comparing to classical PD control algorithm.

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Dynamic Modeling and Model Reduction for a Large Marine Engine

  • Kim, Chae-Sil;Jung, Jong-Ha;Park, Hyung-Ho
    • Journal of the Korean Society of Marine Engineering
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    • v.27 no.4
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    • pp.520-525
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    • 2003
  • This article provides a dynamic modeling methodology of engines to be accurate with a small number of degrees of freedom for an active vibration control using a top bracing. First. a finite element (FE) model for the engine structure is constructed so that the size of model is as small as possible where the dynamic characteristics of engine are ensured. Second. a technique is studied to obtain the exact mass and stiffness matrices of the FE model. The size of matrices from the FE model is still too large to apply. Finally, a model reduction is. therefore. conducted to make an appropriate dynamic model for designing and simulating a top bracing. In this article, a dynamic model of a large 9 cylinder engine is constructed and reviewed by comparing its natural frequencies and steady state reponses with those of experimental data provided by manufacturer.

On the Large Eddy Simulation of Temperature Field Using Dynamic Mixed Model in a Turbulent Channel (동적혼성 모델을 이용한 난류채널의 온도장 해석)

  • Lee Gunho;Na Yang
    • Transactions of the Korean Society of Mechanical Engineers B
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    • v.28 no.10
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    • pp.1255-1263
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    • 2004
  • An a priori test has been conducted for the dynamic mixed model which was generalized for the prediction of passive scalar field in a turbulent channel flow The results from a priori tests indicated that dynamic mixed model is capable of predicting both subgrid-scale heat flux and dissipation rather accurately. The success is attributed to the explicitly calculated resolved term incorporated into the model. The actual test of the model in a LES a posteriori showed that dynamic mixed model is superior to the widely used dynamic Smagorinsky model in the prediction of temperature statistics.

Simulation of Dynamic Characteristics of Agricultural Tractor(I) - Development of 3 Dimensional Dynamic Tractor-Trailer Model - (농용 트랙터의 동특성 시뮬레이션(I) - 3차원 동적 트랙터 -트레일러 모델 개발 -)

  • 박홍제;김경욱
    • Journal of Biosystems Engineering
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    • v.22 no.4
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    • pp.421-432
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    • 1997
  • This study was conducted to investigate dynamic characteristics of agricultural tractor with a particular interest in ride vibrations when it is subjected to various excitation forces. As the first part of it this paper describes development of dynamic model of a tractor-trailer system and its equations of motions. An 3 dimensional 16-degree-of-freedom dynamic model for a tractor-trailer system was developed and its equations of motions were derived, which will be used to investigate the effects of irregular ground surface and excitation forces due to the engine mounted on the tractor. And the excitation forces were also formulated analytically. The transition matrix method and QR algorithm were proposed for numerical solution of the equation of motions fur the developed model. The later parts of the study will include a proof of the model and optimization from which tractors can be designed to minimize the ride vibrations. This will be presented in the second and third papers to be followed shortly.

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