• Journal of the Korean Society of Manufacturing Process Engineers
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• v.15 no.2
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• pp.57-65
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• 2016

The suspension system of a subway vehicle is composed of $1^{st}$ and $2^{nd}$ springs. The suspension system is the most important parameter in determining the vibration ride comfort. If the $1^{st}$ suspension spring is designed as a spring with strong stiffness to improve the running stability at high speed, it causes vehicle vibrations. In this paper, by testing and analyzing changes of the characteristics of Chevron springs, which have been the primary suspension springs used for about 20 years, we study how changing the characteristics affects vehicle acceleration and ride comfort. The lateral and longitudinal vibrational ride comfort index levels were lower than the vertical ones. Therefore, as increasing the stiffness of Chevron springs has the greatest effect on the vertical vibrational ride comfort index level, a countermeasure for vertical vibration reduction is needed when the stiffness increases owing to aging. Finally, maintenance guidelines, including the replacement time for the Chevron rubber, were proposed based on these findings.

• Proceedings of the KSR Conference
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• 2005.05a
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• pp.308-313
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• 2005

An urban railway vehicle has a characteristics such as that a lot of passenger use it and the major of passenger is standee. The ride comfort of standee is greatly influenced by the lateral dynamic characteristics of vehicle. So the lateral vibration is important factor for the improvement of ride comfort. In this study, vibration test of railway vehicle is carried out under the same condition of field driving to find out the major factor of vibration. By considering the test results under the various driving condition, the vibrational characteristics of vehicle is verified.

• Proceedings of the KSR Conference
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• 2010.06a
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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.

• Proceedings of the KSR Conference
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• 2009.05a
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• pp.1566-1573
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• 2009

Although the riding comfort of tilting trains has been managed by setting allowable limits of roll motion in Korea, 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 tilting train on transition curves, 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.

• Proceedings of the KSR Conference
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• 2008.06a
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• pp.1628-1636
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• 2008

Construction of concrete slab track is trending to increase gradually in national and international for reduction in track maintenance cost and secure of ride comfort. But elastic pad becomes superannuated due to repeated train operation. After all, it brings change of pad stiffness and it could directly act on track and bridge as load transmission and impact force. In this study, we carried out laboratory test changing pad stiffness after making a model of 15m bridge and laying concrete slab track. Also, we carried out static and dynamic behaviors test(stress, natural frequency, damping ratio, vibrational acceleration, deflection) of bridge and track and experimentally analyzed them by change of elastic pad stiffness on rail fastener.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.25 no.7
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• pp.1097-1106
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• 2001

A telescopic handless is a kind of construction machinery for loading, carrying and unloading various cargos. A residual vibration of the boom, however, is often caused in carrying cargos to high workplace, especially in small motion and unloading operations, even when an expert of this machine handless the boom. To solve this vibrational problem, we applied TDC and newly proposed Commandless IST to the telescopic handler, and confirmed their effectiveness through experiments. These promising results show that the proposed control schemes can improve productivity, safety and ride comfort of the telescopic handler.