• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.13 no.4
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• pp.266-273
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• 2003

The purpose of this study is to obtain the effects of the parameters of the suspension system in railway rolling-stock for KT-23 type Passenger vehicle. According to the analysis and the small scale model car test. optimal condition was obtained for the stiffness ratio of secondary spring to primary spring of the suspension system and the mass ratio of the bogie frame to the car body. The analysis of the study shows that if the car body mass is increased or secondary stiffness Is lowered, the vertical vibration level is reduced and the passenger comfort can be improved. Especially, strong peaks are occurred in the frequencies corresponding to the rotational speed of driving axle and vehicle wheel. Hence, in order to obtain the dynamic characteristics through the small scale model car, the driving method of the vehicle on the test bench, rotational characteristics of the wheel and the natural modes of vehicle should be investigated and be modified.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.24 no.2
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• pp.146-153
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• 2014

This study investigates the effects of seat-design elements such as seating arrangement, shape, and height on speech privacy in high-speed trains. For the evaluation of speech privacy, acoustic simulation software was used to reproduce room acoustical conditions in passenger cars on the basis of in-situ measurement data. The influences of speech source directivity and source height on privacy distance ($r_P$) were investigated, and it was found that $r_P$ determined using an omni-directional source was relatively shorter than that determined using a directional source. It was also found that $r_P$ decreased when the source height was lower than the height of the seat-back because the seat-back blocked the propagation of speech from the sound source. The effect of seating arrangement was not significant when comparing the vis-a-vis seating and one-side seating arrangements. In addition, among the alternative seat-designs, the seats that block the space between the seats and cover the space near the ear were found to show significantly enhanced speech privacy in high-speed train passenger cars.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2012.04a
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• pp.455-460
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• 2012

Thirteen taxi drivers as the subject in the experiment were exposed to vertical vibration which is controlled on a rigid seat reflecting vibration on passenger vehicle. They were employed not only to get human response of objective measurement but also to make subjective evaluation of the vibration. The subjective evaluation was estimated using the absolute discomfort threshold of the controlled vibration, which was achieved with the three-down one-up method that is widely used in the field of psychophysics. As the result, apparent mass and apparent eccentric mass as objective human response tend to gradually decrease when frequency of the vibration increases. The absolute discomfort threshold was increased in case of increasing the frequency. Concludingly, the subjective discomfort evaluation is highly correlated with the objective human responses at the range of idle vibration on passenger vehicle.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.22 no.5
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• pp.422-428
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• 2012

Thirteen taxi drivers as the subject in the experiment were exposed to vertical vibration which is controlled on a rigid seat reflecting vibration on passenger vehicle. They were employed not only to get human response of objective measurement but also to make subjective evaluation of the vibration. The subjective evaluation was estimated using the absolute discomfort threshold of the controlled vibration, which was achieved with the three-down one-up method that is widely used in the field of psychophysics. As the result, apparent mass and apparent eccentric mass as objective human response tend to gradually decrease when frequency of the vibration increases. The absolute discomfort threshold was increased in case of increasing the frequency. Concludingly, the subjective discomfort evaluation is highly correlated with the objective human responses at the range of idle vibration on passenger vehicle.

• Proceedings of the KSR Conference
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• 2011.10a
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• pp.57-61
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• 2011

The bimodal tram was designed to drive on the dedicated track as well as on the public road. The position and speed are automatically controlled on the dedicated track by the onboard computer, whereas they are manually controlled by driver like motor vehicles on the public road. The ride comfort the passengers feel and the effect of the vibration generated during driving on the passenger's health, comfortableness and motion sickness were evaluated with driving the bimodal tram prototype in automatic and manual mode, respectively. The test was done in automatic mode on the test track with various load conditions while it was done in manual mode on the public road with empty load.

• Transactions of the Korean Society of Automotive Engineers
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• v.5 no.5
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• pp.20-26
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• 1997

A System for reducing vehicle body roll by active control is developed. The stabilizer bar with hydraulic rotary actuator produces anti-roll moment which suppresses roll tendency. This reduction of roll improves the driving safety as well as the ride comfort. Vehicle test data shows considerable reduction of roll angle during steady-state turning. Also improvement of ride comfort is achieved by making the actuator freely rotatable, i.e. by connecting all chambers of actuator in normal driving conditions. A control algorithm using steering wheel angle and vehicle speed signal as input valve is applied. It is compared with signal of the G-sensor.

• Proceedings of the KSR Conference
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• 2010.06a
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• pp.1444-1451
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• 2010

This paper aims for proposed the deflection limit on vibration serviceability of high-speed railway bridges considering the exposed time duration when a train passes a railway bridge. For this purpose, bridge-train transfer function was derived and bridge-train interaction analysis was performed by using the derived function. The vertical acceleration signals of passenger cars obtained from bridge-train interaction analysis were compared with them from the bridge-train transfer function by moving constant force analysis. Therefore it was estimated possible to induce the comfort deflection limit of railway bridge by using bridge-train transfer function. The deflections by moving force of single span bridge and continuous bridge were assumed as sine and haversine wave. The deflection limit on vibration serviceability of high-speed railway bridges considering the exposed time duration can be expanded using bridge-train transfer function and bridge comfort limit considering serviceability due to bridge vibration. And it was compared to other allowable deflection limits of railway bridge design specifications.

• Proceedings of the KSR Conference
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• 2003.10c
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• pp.28-35
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• 2003

In this paper, the ride comfort of a passenger coach installed with a KT23 type bogie was measured and evaluated through field test in operation routes. The ride comfort level was evaluated and analysed by ISO method and DIC method that were applied generally at railway fields. Particularly three evaluation methods, i.e., a simple method, a full standing method, and a full seating method of UIC513R standard, were fully applied to evaluate the ride quality. Also the vertical and lateral vibration levels on the floor were evaluated by peak-to-peak analysis method.

• Journal of the Society of Naval Architects of Korea
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• v.46 no.6
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• pp.631-640
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• 2009

The highest priority of the cruise trip is the safety and comfort of its passengers. Though the cruise lines take every appropriate measure to ensure that their Passengers are safe and experience enjoyable vacations it is hard to fulfill all passenger's personnel requirement with limited number of crews. Generally, each passenger is issued an identification card which contains their digital photo and personal identification information on a magnetic strip that he or she must present when entering or leaving the ship. This technology allows the ship to know which Passengers and crew members are on board and which are not. However, this system has some limitations of functions and usage. To support each passenger as his or her personal liking, additional number of crews or some kind of new system is needed. In this paper, the crew support system based on sensor network using wireless and wired communication technologies was studied. To design the system, PLC(Power Line Communication) system and ZigBee based passenger location recognition, classification system has studied experimentally. By using this system, crews can serve passengers more closely and personally with less effort.

• Journal of the Korean Society for Precision Engineering
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• v.28 no.1
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• pp.31-39
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• 2011

This paper presents design and control of a quarter-vehicle magneto-rheological (MR) suspension system for ECS (electronic control suspension). In order to achieve this goal, MR shock absorber is designed and manufactured based on the optimized damping force levels and mechanical dimensions required for a commercial mid-sized passenger vehicle. After experimentally evaluating dynamic characteristics of the manufactured MR shock absorber, the quarter-vehicle MR suspension system consisting of sprung mass, spring, tire and the MR shock absorber is constructed in order to investigate the ride comfort and driving stability. After deriving the equations of the motion for the proposed quarter-vehicle MR suspension system, the skyhook controller is then implemented for the realization of quarter-vehicle MR suspension system. In order to present control performance of MR shock absorber for ECS, ride comfort and driving stability characteristics such as vertical acceleration of sprung mass and tire deflection are experimentally evaluated under various road conditions and presented in both time and frequency domain.