• 한국정밀공학회지
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• 제16권12호
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• pp.214-221
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• 1999

In this research, a power-assisted steering system is modeled as a part of a full vehicle dynamic model. The dynamic model of the steering system incorporates hydraulic and dynamic relations between major parts of a steering system, such as steering column, control valve, rack and pinion gear. Through an experimental setup of the steering system, the steering system model is validated. The steering model is included in a full vehicle dynamic model of a car, where kinematic relations between steering and suspension system are defined, and various simulations are performed to evaluate the performance of steering system in conjunction with overall dynamic performance of the vehicle.

• 한국정밀공학회지
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• 제20권6호
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• pp.178-188
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• 2003

A study on the dynamic analysis of a tracked vehicle for mining on deep-sea bed with very soft soil is presented. An equation for the interaction between track and soft soil is employed to develop a track/soil interaction module called TVAS. The vehicle is modeled as a multi-body dynamic system using a multi-body dynamic analysis program. The developed module is incorporated into the multi-body dynamic analysis program with a user subroutine. The dynamic behavior and design of the mining vehicle on deep-sea bed is investigated.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2004년도 추계학술대회 논문집
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• pp.363-368
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• 2004

Maglev vehicles, which are levitated and propelled by electromagnets, often run on elevated guideways comprised of steel, aluminum and concrete. Therefore, an analysis of the dynamic interaction between the Maglev vehicle and the guideway is needed in the design of the critical speed, ride, controller design and weight reduction of the guideway. This study introduces a dynamic interaction simulation technique that applies FEM. The proposed method uses FEM to model the elevated guideway and the Maglev vehicle, which is different from conventional studies. Because the proposed method uses FEM, it is useful to calculate the deformation of the elevated guideway, the dynamic stress, and the motion of the vehicle. By applying the proposed method to an urban transit Maglev vehicle, UTM01, the dynamic response is simulated according to velocity increase and can be reviewed again. From the result of the study, we concluded that FEM simulation of the dynamic interaction between the maglev vehicle and the guideway is possible.

• 한국공작기계학회논문집
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• 제12권4호
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• pp.57-62
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• 2003

A fundamental structural design consideration for a vehicle system is the overall vibration characteristics in bending and torsion. Vibration characteristics of such vehicle system are mainly influenced by the static and dynamic stiffness of the vehicle body structure and also by the material and physical properties of the components attached to the vehicle body structure. In this paper, modeling techniques for the vehicle components are presented and the flexibility and mass effects of the components for the vibration characteristics of the vehicle are investigated. The $1^{st}$ torsional frequency is increased by attaching windshields to the B.I.W. (body-in-white), but the $1^{st}$ bending frequency is decreased by the mass effect. And also, the natural frequencies of the vehicle are large decreased by attaching bumpers, seats, doors, trunk-lid etc. But, suspension system rarely affects the natural frequencies of the vehicle. The study shows thai the dynamic characteristics of the vehicle system can be effectively predicted in the initial design stage.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 2000년도 제15차 학술회의논문집
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• pp.306-306
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• 2000

This paper analyze the dynamic characteristics of Automated Guided Vehicle(AGV) which is being developed as a part of automation in port through DADS, one of the multi-dynamic analysis program, Previous evaluation of a vehicle is carried out through the continuous driving test of a real vehicle, however this method raise the loss of finance and time. If it is possible to analyze the dynamic characteristics of vehicle before construction completely we can compensate the loss of money and time during constructing. AGV contained containers is very heavy and its center of gravity can be easily changed with the disturbance from road or cornering. It makes AGV unsatisfied, therefore we evaluate the handling characteristics and stability of the full vehicle model. This paper contribute to establish the foundation of the development of a new system like a AGV which have a special structure.

• 전기학회논문지
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• 제63권1호
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• pp.162-172
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• 2014

A three-dimensional dynamic model for simulating various motions of full vehicle is presented. The model has 16 independent degrees of freedom (DOF) consisting of three kinds of components; a vehicle body of 6 DOF, 4 independent suspensions equipped at every corner of the body, and 4 tire models linked with each suspension. The dynamic equations are represented in six coordinate frames such as world fixed coordinate, vehicle fixed coordinate, and four wheel fixed coordinate frames. Then these lead to the approximated prediction model of vehicle posture. Both lateral and longitudinal dynamics can be computed simultaneously under the conditions of which various inputs including steering command, driving torque, gravity, rolling resistance of tire, aerodynamic resistance, etc. are considered. It is shown through simulations that the proposed 3D model can be useful for precise design and performance analysis of any full vehicle control systems.

• 제어로봇시스템학회논문지
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• 제18권4호
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• pp.359-364
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• 2012

Real-Time Traversability should be analyzed from the equiped sensors' data in real time for autonomous outdoor navigation. However, it is difficult to find out such traversability that considers the terrain roughness and the vehicle dynamics especially in case of skid type vehicle. The traversability based on real time dynamic analysis was proposed to solve such problem but in navigation with strait driving path. To adapt the method into the navigation with curved driving path, a path following controller should be incorporated into the dynamic model even though it cause the real time problem. In this paper, a dynamic model is proposed to solve the real time problem in the traversability analysis based on real time dynamic simualtion. The dynamic model contains the control dummy which is connected to the vehicle body with a universal joint to follow the curved path without controller. Simulation and experimental results on $6{\times}6$ articulated unmanned ground vehicle demonstrate the method's effectiveness and applicability into the traversability analysis on terrain with bumps.

• Structural Engineering and Mechanics
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• 제54권3호
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• pp.561-577
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• 2015

The main objective of this paper is to study the dynamic load allowance (DLA) calculation methods for bridges according to the dynamic response curve. A simply-supported concrete bridge with a smooth road surface was taken as an example. A half-vehicle model was employed to calculate the dynamic response of deflection and bending moment in the mid-span section under different vehicle speeds using the vehicle-bridge coupling method. Firstly, DLAs from the conventional methods and code provisions were analyzed and critically evaluated. Then, two improved computing approaches for DLA were proposed. In the first approach, the maximum dynamic response and its corresponding static response or its corresponding minimum response were selected to calculate DLA. The second approach utilized weighted average method to take account of multi-local DLAs. Finally, the DLAs from two approaches were compared with those from other methods. The results show that DLAs obtained from the proposed approaches are greater than those from the conventional methods, which indicate that the current conventional methods underestimate the dynamic response of the structure. The authors recommend that the weighted average method based on experiments be used to compute DLAs because it can reflect the vehicle's whole impact on the bridge.

• Smart Structures and Systems
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• 제31권2호
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• pp.155-169
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• 2023

The quasi-static component of the moving vehicle-induced dynamic response is promising in damage detection as it is sensitive to bridge damage but insensitive to environmental changes. However, accurate extraction of quasi-static component from the dynamic response is challenging especially when the vehicle velocity is high. This paper proposes an adaptive quasi-static component extraction method based on the modified variational mode decomposition (VMD) algorithm. Firstly the analytical solutions of the frequency components caused by road surface roughness, high-frequency dynamic components controlled by bridge natural frequency and quasi-static components in the vehicle-induced bridge response are derived. Then a modified VMD algorithm based on particle swarm algorithm (PSO) and mutual information entropy (MIE) criterion is proposed to adaptively extract the quasi-static components from the vehicle-induced bridge dynamic response. Numerical simulations and real bridge tests are conducted to demonstrate the feasibility of the proposed extraction method. The results indicate that the improved VMD algorithm could extract the quasi-static component of the vehicle-induced bridge dynamic response with high accuracy in the presence of the road surface roughness and measurement noise.

• 한국자동차공학회논문집
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• 제12권4호
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• pp.163-172
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• 2004

Nowadays, to analyze the dynamic characteristics of the automotive driving system, the computer simulation linked up with VR(Virtual Reality) technology is treated as the useful method with the improvement of computing ability. In this paper, the VR simulation system has been developed to investigate the driving characteristics of the ASV(Advanced Safety Vehicle) equipped with an ACC(Adaptive Cruise Control) system. For the purpose, VR environment which generates 3D graphic and sound information of the vehicle, the road, the facilities, and the terrain has been organized for the driving reality. Mathematical models of vehicle dynamic analysis including the ACC model have been constructed for computer simulation. The ACC modulates the throttle and brake functions to regulate the vehicle speed so that vehicles could keep proper spacing. Also, the real-time simulation algorithm synchronizes vehicle dynamic simulation with the graphic rendering. With the developed VR simulation system, simple scenarios are applied to analyze the dynamic characteristics. It is shown that the VR simulation system could be useful to evaluate the adaptive cruise controlled vehicle on various driving conditions.