• 대한기계학회:학술대회논문집
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• 대한기계학회 2001년도 추계학술대회논문집A
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• pp.483-488
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• 2001

As the technique of automobile industry is being advanced, the advancement of vehicle ride is being required. In order to achieve this purpose, the study on the vibration which are produced by moving vehicle is carried out actively. In this study, the tire vibration characteristics for passing over a cleat are analyzed. The model is verified against simulations and experiments. The tire is modeled with 7-DOFs (degree of freedom), and the effects of changing tire design parameters are considered. According to the results of analysis, the design parameters that reduce the tire and wheel vibration energy are conducted.

• Journal of Mechanical Science and Technology
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• 제17권7호
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• pp.958-965
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• 2003

Structural integrity of either a passenger car or a light truck is one of the basic requirements for a full vehicle engineering and development program. The results of the vehicle product performance are measured in terms of ride and handling, durability, noise/vibration/harshness (NVH), crashworthiness and occupant safety. The level of performance of a vehicle directly affects the marketability, profitability and, most importantly, the future of the automobile manufacturer In this study, we used the virtual proving ground (VPG) approach for obtaining the dynamic characteristics. The VPG approach uses a nonlinear dynamic finite element code (LS-DYNA3D) which expands the application boundary outside the classic linear static assumptions. The VPG approach also uses realistic boundary conditions of tire/road surface interactions. To verify the predicted dynamic results, a single lane change test has been performed. The prediction results were compared with the experimental results, and the feasibility of the integrated CAE analysis methodology was verified.

• 한국소음진동공학회논문집
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• 제26권7호
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• pp.827-835
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• 2016

Ride comfort of a vehicle is often determined by rubber bushes in suspension system. If transmission forces versus deformations across the bushes are available under operational conditions, improvement of the ride comfort could be done with more ease. Recently, the transmission forces are measured using custom-made force transducers inside the links. This study presents a feasibility study on estimation of the rubber bush deformations using vibration signals on the rigid links. Linear variable displacement transducers as well as piezoelectric accelerometers are used to expand frequency range to very low frequency, which cannot be done with accelerometers only. How to estimate the bush deformation from the two vibration signals on the links are presented together with experimental results.

• 제어로봇시스템학회논문지
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• 제16권11호
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• pp.1096-1103
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• 2010

This paper proposes CDC (Continuous Damping Control) algorithm and verifies in multi-body dynamic vehicle. In order to distinguish a road profile on driving, waviness calculated by the filtered vertical-accelerations of sprung and unsprung masses is introduced. Sky-hook control is used at a low waviness road and constant damping level control is used at a high waviness road, where the hard damping level is determined by waviness, roll rate, acceleration, and deceleration. The damping levels of ride, anti-roll, anti-squat, and anti-dive modules are calculated by tuning parameters which is dependent upon vehicle velocity. Therefore this high tunable algorithm is useful to improve the ride and handling performance under various driving conditions. In the simulations, tire and dampers are modelled by SWIFT (Short Wavelength Intermediate Frequency Tire) model and 1st order delay model, and results are compared with conventional damper's.

• 한국철도학회논문집
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• 제8권2호
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• pp.182-187
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• 2005

Air spring system was widely accepted for railway vehicle secondary suspension to reduce and absorb the vibration and noise. The low natural frequency ensures a comfortable ride and an invariably good stiffness. In this paper, the characteristics and durability test was conducted in laboratory by using servo-hydraulic fatigue testing system to reliability evaluation of air spring for electric railway vehicle. The experimental results show that the characteristics and durability of domestically developed productions are shown in good results. And to guarantee the adaption of air spring, the ride comfort and air pressure variation were measured in train test on subway line.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2005년도 춘계학술대회 논문집
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• pp.473-478
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• 2005

Active suspension system improves ride quality with optimized suspension force, generated by electric, hydrolic or pneumatic power and controlled by micro-processor under various operation condition of train, while Semi-Active susepsion system provides optimized and controlled characteristics of suspensions such as damping coefficient without external energy. The benefits fo Semi-Active suspension are no required power source and to be made compact with lower cost. Train with narrow gauge could be more unstable than one for normal or wide gauge, and it could be more vibrated than others one by external force such as aerodynamic force and track irregularity. So, the reduced ride quality could be improved with appling with Semi-active suspension system. In this report, the Semi-Active suspension system for narrow gauge train shall be proposed and to prepare the Roller Rig test of this train, integration of system, development of control algorithm and confirmation of its performance with simulation tool would be taken.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2007년도 춘계학술대회 논문집
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• pp.188-193
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• 2007

Airport railroad have required maximum design speed 120km/h and wind speed 50m/s condition as design item of airport railroad vehicles. To design and manufacture the vehicle satisfying these conditions, it must carry out the dynamic behaviors analysis such as hunting stability, ride comfort derailment ratio, unloading ratio and lateral force to meet the criterion described in Urban Railroad Act. Dynamic behaviors of vehicle have carried out using the multi-body dynamics simulation program(VAMPIRE). This paper presents the evaluation methods and criterion used to verify dynamic performance of airport railroad vehicle, and show the analysis results of vehicle dynamic simulation and the test results for vibration and ride comfort measured on running performance tests. As a results, each analysis results and test results meet the criterion described in Urban Railroad Act.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2010년도 춘계학술대회 논문집
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• pp.1017-1025
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• 2010

The Purpose of this paper is to characteristics and analysis of ride comfort by using HRV. Although the riding comfort of trains has been managed by setting allowable accelerations of 3-axis motion in cabins, it is impossible for this approach to express the psychophysical relationship between various vibrational factors and riding comfort. in order to propose a function to evaluate the riding comfort of train on conventional railroad, an experiment was performed with the Korea Tilting Tran eXpress(TTX). As a result, by referring to some international standards on the method of evaluating ride comfort, a modified method was proposed to evaluate the lateral vibration in addition to the roll motion on carve transitions.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2007년도 추계학술대회 논문집
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• pp.1324-1329
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• 2007

For the commercialization of the urban maglev, an articulated turnout which consists of several segments of turnout girders and where switching is done by rotating those segments is under development. In this paper, to determine the alignment of this articulated turnout, the requirements for the alignement are analyzed. Requirements include: those for the levitation control and for the ride comfort. For the levitation control, rail joint width should be limited to a certain value, and for the ride comfort, the lateral acceleration and the time derivative of the lateral acceleration satisfy a guideline. According to these requirements, the alignment criteria are discussed.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2000년도 춘계학술대회논문집
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• pp.132-137
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• 2000

차량 개발에 있어서 승차감(Ride)과 조향성능(Handling)의 평가는 차량의 동적 성능을 판단하는 주 인자인데, 차량업계에서는 이들 평가의 대부분을 주관적인 방법에 의존하고 있다. 최근에는 주관평가의 문제점을 해소하기 위해 차량의 동적 거동을 직접 측정함으로써 평가를 객관화하려는 시도가 많이 행해지고 있다. 본 연구에서는 숭차감 평가를 위한 정량화 지수를 개발하는데 있어서 저해 요인들을 분석하고 이에 대한 해결방안을 제안함으로써 측정된 물리량을 이용하여 주관평가 결과를 대체할 수 있는 방안을 정립하고자 한다. 우선 정적, 동적 승차감에 대한 모형을 통해서 승차감 정량화의 한계와 기존의 승차감 평가지수에 대해 고찰하고, 실제 차량 시험에서 얻어진 주관 평가치와 측정 가속도간의 상관관계 정립을 통해 관계식을 수립하는 방안에 대해 서술하고자 한다. 이 과정에서 주행시 간헐적으로 들어오는 충격성 입력을 처리하는 방법도 함께 논하였다.