• Title/Summary/Keyword: ride safety

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A Fundamental Study on the Control of Ride Comfort and Attitude for In-wheel Motor Vehicles (인휠모터 구동차량의 승차감 및 자세제어를 위한 기초적 연구)

  • Kim, Y.R.;Park, C.;Wang, G.N.
    • Journal of Power System Engineering
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    • v.16 no.1
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    • pp.91-97
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    • 2012
  • It is being accelerated to develop environment-friendly vehicles to solve problems on the energy and environment of earth. The electric driving motor commonly installed in these vehicles has the excellent control capability such as fast response and accurate generation to torque control command. Especially, in-wheel motor has the additional merit such as independently driving each wheel in vehicle. Recently, being developed various control algorithm to enhance the safety and stability of vehicle motion using actively the merits of in-wheel motor. In addition to that, being issued the possibility of enhancing the ride comfort and attitude of vehicle motion such as pitching and rolling. In this paper, investigate the theoretical relationship between the braking/driving force and the motion of sprung mass of vehicle and propose the control method to enhance the ride comfort and attitude of vehicle motion. The proposed control method is proved through the simulation with vehicle model provided by TruckSim software which is commercial one and specializes in vehicle dynamics.

Analysis of Continuously Variable Damper Characteristics for Semi-Active Suspension Systems (반능동형 현가시스템을 위한 연속가변댐퍼의 특성 해석)

  • 허승진;박기홍
    • Journal of the Korean Society for Precision Engineering
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    • v.20 no.7
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    • pp.128-137
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    • 2003
  • Continuously variable damper can yield diverse damping forces for a single damping velocity. It is widely used in the semi-active suspension system since, with right control logics, it can enhance ride comfort compared to the passive damper while not degrading driving safety. A key to the successful design of the continuously variable damper is the knowledge of its complex and nonlinear characteristics. In this paper, research has been done for analyzing characteristics of the continuously variable damper. Various damper components have been investigated and their effects upon the force-velocity characteristics of the damper have been examined. The effects of the damper characteristics change upon ride comfort and driving safety have also been investigated by numerical simulations.

Analysis of Dynamic Behaviors for the Korea High Speed Train(KHST) by Using Non-Linear Creep Theory (비선형 크립이론을 이용한 한국형 고속전철의 동특성 해석)

  • 박찬경;김석원;김회선
    • Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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    • 2002.05a
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    • pp.1093-1098
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    • 2002
  • Dynamic behaviors of the Korean High-speed Train(KHST) have been analyzed to investigate the performance on the stability, the safety and the ride comfort. Multi-body dynamics analysis program using Recursive method, called RecurDyn, have been employed in the numerical simulation. To model the wheel-rail contact, the RecurDyn uses its built-in module which uses the square root creep law. The accuracy of the rail module in RecurDyn. however, decreases in the analysis of flange contact because it linearizes the shape of the wheel and rail. To solve this problem, a nonlinear contact theory have been developed that considers the profiles of the wheel and rail. The results show that the KHST still needs more stability. The problem should be solved by the examinations of module and modeling.

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Running Performance Analysis of an Articulated Light Rail Vehicle (관절형 경량전철의 주행성능 해석)

  • Hur, Shin;Park, Chan-Kyung;Han, Hyung-Suk;Ha, Sung-Do
    • Proceedings of the KSR Conference
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    • 1999.05a
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    • pp.159-166
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    • 1999
  • In this paper, running performance analyses of an articulated light rail vehicle are carried out using VAMPIRE software package. The stability analysis to determine the critical speed and the safety analysis such as derailment coefficients, lateral forces of wheels and reduction of wheel load are carried for the track conditions of straight, transition and curving range to the operating velocity of 40km/h. Also, ride quality is analyzed. As the results of analysis, the safety of light rail vehicle satisfied with the limit values and the ride quality for tare and full load condition was shown to the "not uncomfortable" level in ISO 2631-1 (1997) criteria.

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ECO Driving Patterns Derived from the Analysis of the Problems of the Current Driving Pattern of Electric Multiple Unit in ATO System (현행 ATO 시스템 전동차 운행패턴의 문제점 분석을 통한 ECO 운행패턴 도출방안 연구)

  • Kim, Kyujoong;Lee, Keunoh;Kim, Juyong
    • Journal of the Korean Society of Safety
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    • v.28 no.3
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    • pp.23-28
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    • 2013
  • This study focuses on finding ways to derive train's optimal ECO driving pattern, which can improve the ride quality and reduce driving energy consumption with keeping the time interval between the stations. As research method, we compared difference of currently operating train's ATO and MCS driving patterns, and concentrated upon the things need to consider in simulation in order to improve the existing pattern of ATO driving pattern's issues with securing the train operation safety. Determining driving pattern minimizing energy consumption by controlling powering within speed limit and controlling switching to coasting at appropriate point considering the track conditions for each section, and determining braking control starting time considering ride comfort and precise stopping is considered to be most important.

Safety evaluation of dynamic behavior of Korean tilting train (TTX차량의 동역학적 거동의 안정성 평가)

  • Yoon, Ji-Won;Kim, Nam-Po;Kim, Young-Guk;Kim, Seog-Won;Park, Tae-Won
    • Journal of the Korean Society for Railway
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    • v.10 no.5
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    • pp.540-545
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    • 2007
  • The tilting train is able to tilt its body towards the center of the turning radius, preventing roll-over of the train as it runs on a curved rail at high-speed. This train, widely accepted for commercial purpose internationally, is very beneficial in that the operating time is shortened without much capital investment to the infrastructure where there are many curved rails. Over several years, the Korea Railroad Research Institute (KRRI) has developed such a train. In this paper, the safety of the Korean tilting train express (TTX) is investigated using a dynamic simulation model. Since proper safety standards have not been established for the TTX, those for the Korean train express (KTX) is employed to analyze the safety and ride comfort of the TTX. This study is useful in predicting the behavior of the TTX and ride comfort, and conforms that designed TTX is stable enough to satisfy the safety standards. It would be useful to recommend proper normal operating speed and determine the maximum safety speed, according to the result. Furthermore, it would be possible to provide basic reference data when analyzing the dynamic effect of the catenary system and the fatigue of the bogie.

A Experimental Research on Stair Ascent Evacuation Support for Vulnerable People (안전약자 상층 대피 지원에 관한 실험적 연구)

  • Lee, Ji Hyang;Lee, Hyo Jeong;Kwon, Jin Suk;Park, Sang Hyun
    • Journal of the Korean Society of Safety
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    • v.34 no.1
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    • pp.90-97
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    • 2019
  • This study is aiming to compare stair ascent transportation speed and physical burden of evacuation supporters according to the types of stair ascent transportation for vulnerable people experimentally. In this study, we measured heart rate of the supporters to indicate physical burden during the transportation. The subjects of this experiment were male students, age of 20-26. Experimental conditions were the ways of stair transportation and the weight of vulnerable people. The types of stair transportation were giving a piggyback ride and carrying a wheelchair. Each experimental trial was video-recorded for measurement of ascent speed and observing supporters movement. As a result of the experiment, as for the ascent transportation speed by piggyback ride from the first floor to the fourth floor, the average speed of the light case is 31 seconds and for the heavy case is 43 seconds. When it comes to the average speed of wheelchair transportation's average speed the light case is 1 minute and 11 seconds and the heavy case is 1 minute and 49 seconds. Therefore, it was indicated that when the weight of a vulnerable people is lighter, the transportation speed is faster. The heart rates of evacuation supporters are different depending on transportation methods or individual's condition but as repetitive transportation increases, they tend to reach the maximum heart rates.

A Study on Ride Quality Due to Deterioration Effects for the Coupler Types of Urban EMUs (도시철도차량의 연결기 종류별 노후화가 승차감에 미치는 영향 연구)

  • Kim, Jun Woo;Cho, Byung Jin;Han, Eun Kwang;Koo, Jeong Seo
    • Journal of the Korean Society of Safety
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    • v.32 no.3
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    • pp.117-122
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    • 2017
  • In this study, we studied the ride quality considering the deterioration effects of the three type couplers (single, double, and ring types) for EMUs. In order to know the impact occurred when an urban transit vehicle is under breaking, we tested the conditions of the service brake and the emergency brake. Normal coupler models without any slack showed similar dynamic performance results under all breaking conditions. But if the couplers become old, the initial pre-stresses are removed because of permanent compressive deformation in rubber. For three types of the old coupler models without the initial pre-stress, we evaluated dynamic performances of each type. As the results, the maximum and average acceleration levels of the double type and the ring type were similarly low in all conditions. But the accelerations of the single type coupler was high when compared to those of the double and ring types. In addition, Jerk value of the single type model associated with ride quality was high up to 15 times to the ring type in condition of the service braking in empty vehicle weight. Jerk value of the double type model was high up to 6 times to the ring type.

A Study on the Optimization of Suspension Characteristics for Improving Running Safety of Railway Vehicle (철도차량 주행안전성 향상을 위한 현가장치 최적화 연구)

  • Lee, Young-Yeob;Lee, Hi-Sung
    • Journal of the Korean Society for Railway
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    • v.12 no.6
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    • pp.909-914
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    • 2009
  • A suspension is the most prior apparatus to decide vehicle's running safety and ride comfort, also the suspension stiffness is the most important parameter for the designing of the vehicle. Providing the strong stiffness with the primary suspension in order to improve the running safety with high speed, but it causes a problem with a curve running performance of a railway vehicle. Therefore, many studies deal with the optimal value of suspension stiffness. In this paper, we aim to optimize the suspension system to improve running safety by varying stiffness values of railway vehicle suspension. We have proceeded an analysis by design variables which are position, length, width, stiffness and damping coefficients of primary and secondary suspension to optimize the suspension characteristics. As a result of the optimization, we verified that the derailment coefficients of inside and outside of wheel are decreased in comparison with initial model.

Effect of Damper Between Maglev Vehicles on Curve Negotiation (자기부상열차 차간 댐퍼의 곡선주행에의 효과 분석)

  • Kim, Ki-Jung;Han, Hyung-Suk;Kim, Chang-Hyun;Yang, Seok-Jo
    • Transactions of the Korean Society of Mechanical Engineers A
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    • v.37 no.4
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    • pp.581-587
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    • 2013
  • In a magnetic train set composed of more than two cars, the installation of dampers between cars is carefully considered for improving both the ride quality and the safety, particularly during curve negotiation. In this study, a dynamic simulation of the ride quality and curve negotiation of a Maglev vehicle was carried out. The dynamic model is developed based on multibody dynamics. The presented full vehicle multibody dynamic model integrates the electromagnet model and its control algorithm. By using this model, the effects of the dampers are numerically analyzed. The proposed damper is installed on the vehicle and tested to analyze its effects. In this study, the simulation and measured results of the vehicle behavior and ride quality are discussed.