• Transactions of the Korean Society of Mechanical Engineers A
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• v.41 no.10
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• pp.967-974
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• 2017

In this paper, a differential-braking-based yaw moment control system was developed to guarantee robust performance against road bank angle. A new target yaw rate model was established by combining the signal from a lateral acceleration sensor and 2-DOF single track model. In addition, a disturbance observer was utilized to take into account parameter uncertainties in yaw dynamics and to improve robust performance of the controller. CARSIM, which is a multi-DOF vehicle dynamic simulation tool, was used to verify the performance of the proposed controller in various driving scenarios. The simulation results indicate that the stability of the vehicle was robustly maintained by the controller, which is characterized by the reflection of the signal of a lateral acceleration sensor signal and by the compensation of the errors in the model parameters via the disturbance observer.

• Journal of the Korean Society for Railway
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• v.13 no.6
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• pp.583-588
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• 2010

Track irregularities is one of key factors influencing running behavior of train. In order to ensure safety and ride comfort, it is highly important that relationship between track irregularity and running behavior of vehicle is identified and the criteria for track irregularities is adequately established. Numerical analysis was conducted to investigate influence of surface on running behavior of KTX and various wavelength and amplitude of surface were considered in numerical analysis. Derailment, lateral load, bogie acc., body acc. of numerical analysis results were investigated to evaluate the effect on track profile on safety and ride comfort of KTX.

• Journal of Satellite, Information and Communications
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• v.10 no.3
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• pp.68-72
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• 2015

The railway system has been recognized as one of the best eco-friendly advanced transportation systems. Furthermore, the improvement of the passenger transportation quality and the energy saving have been studied for being the most competitive transportation system. However, most of the studies have been mainly focused on the improvement of the transportation efficiency and energy saving because of the characteristics of the urban railway which serves the unspecified multiple passengers. In this paper, the 3-dimensional vibratory lateral acceleration has been measured in various environments for the automatic and manual operation modes of the general train and express train in the urban railway lines. In terms of the improvement of the passenger transportation quality, the comparison analysis of the ride quality is carried out based on the measured 3-dimensional vibratory lateral acceleration and the statistical techniques of UIC513R suggested by the International Union of Railways.

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.14 no.2
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• pp.229-239
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• 1996

for shortening of running time on existing line, speed up railways feel strongly the necessity of it, for fully realizing a role of transportation system, for human life style is high. and increasing of time value. Especially curved lines zone have crucial effects on the speed of train, in case the shortening of running time, it is thought, speed up in curved lines zone, considering a character of route alignment in korea, we obtain saving time using lateral force index for safety running of train and comfortable ride of passengers. The results of this study show that all curved zone improvements for the shortening of the train running time more efficiently than extension of transition curve.

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.13 no.2
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• pp.209-218
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• 1995

It is important role that railway speed up plays in realizing an affluent society in future. Curved lines zone have crucial effects on the speed of train travel, at the curved lines zone, it requires to set cant and slack for safety running of train and comfortable ride of passengers, a compromise is therefore to accept a certain degree of cantdeflciencyforthevarioustrain. In this study, it was presented that effective maintenance method according to the investigation of cant value in radius of curvature and analysis safety running of train, calculation of lateral acceleration as cant deficiency, and we obtain the effect of speed up appling route alignment improvement parameter in curved lines zone.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2014.10a
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• pp.612-617
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• 2014

It is generally known that the automotive road wheel involves the non-proportional multiaxial loading condition, therefore the measuring dynamic stress and strain in driving state is very important to predict an endurance characteristic of the automotive road wheel. In this study, the ultimate driving test using F1 circuit with respect to 2 kinds of velocity conditions have been carried out in order to measure dynamic stress, strain of the wheel and acceleration of a vehicle. Based on the measured results, the characteristics of dynamic stress generation have been analyzed, and factors which have effect on the dynamic stress generation have been studied.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.13 no.2
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• pp.25-32
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• 2013

Entry speed of the vehicle and lateral acceleration acting on the vehicle, roll-angle associated with the overthrow, and then the structure of the road, the friction of road surface are important factors in turning on the curved road. In this study, we analyzed the state change of the vehicle causing entry speed of the vehicle and superelevation of the road, the friction coefficient by using a PC-crash Program for traffic accident reconstruction. As a result, when vehicle is turning the curved road, we could ascertain that the structure of the road and state of the road surface are a major factor about the set up of limited speed.

• Transactions of the Korean Society of Automotive Engineers
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• v.2 no.5
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• pp.101-109
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• 1994

Recently, four-wheel steering systems have been developed and studied as one of the latest automotive technologies for improving the handling characteristics of a vehicle. In much of the proposed four-wheel steering systems, the side slip angle at the vehicle's center of gravity is maintained at zero. This approach allows the greater maneuverability at low speed by means of counter-phase rear steering and the improved stability at high speed through same-phase rear steering. In this paper, the effects of several four-wheel steering systems are studied and discussed on the responsiveness and stability of the vehicle by using the linear analysis. Especially, the effects of the cornering stiffnesses of both front and rear wheels are investigated on the yaw velocity gain and critical speed of the vehicle.

• Journal of the Korean Society for Railway
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• v.9 no.2 s.33
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• pp.145-150
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• 2006

In this study, overturning safety for a tilting train has been evaluated. In the tilting train, the overturning safety is one of the most important factors because the carbody inclines inward a curve during curve negotiation. Dynamic analysis considering unbalanced lateral acceleration and carbody tilting has been carried out and the overturning safety for the tilting train has been evaluated according to height of CG of carbody. From these studies, the overturning safety for the tilting train under unbalanced lateral acceleration of $2m/s^2$ was superior to the conventional one at the same running speed.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2013.04a
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• pp.623-625
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• 2013

Tire hydroplaning is one of the most important tire performances, especially for safety on wet road surface. And nowadays various methods such as FEM and FVM analysis are being applied to design and improve tire hydroplaning performance, along with on-vehicle test of tire hydroplaning. Conventional evaluation of tire hydroplaning has been done by comparing peak lateral acceleration and vehicle speed in time domain. But in this paper, frequency domain analysis of lateral acceleration when hydroplaning at high speed has been carried out to get the quantitative comparison between test tires. And it is concluded that the frequency spectrum analysis of lateral acceleration gives much better discrimination, as compared to the conventional time domain analysis of lateral acceleration and vehicle speed.