• Proceedings of the KSR Conference
• /
• 2005.05a
• /
• pp.20-26
• /
• 2005

A running-profile generation method has been developed that efficiently generates the minimum-energy running profile, even in railway lines which have complicated speed limit sections. In the developed method, the problem of minimizing energy consumption is formulated as a resource allocation problem by dividing a running profile into several blocks, and is solved by the incremental method. A concept of Uni-Braking Block (UBB) which has only one brake section within it is introduces for the formulation. This paper proposes a specific method for running profile in the railway lines by using UBB. And proposes the algorithm to generate the running profile with minimum-energy.

• International Journal of Railway
• /
• v.3 no.2
• /
• pp.68-72
• /
• 2010

Railway vehicles equipped with semi-active suspension system can improve the ride quality of car bodies. Semi-active suspension system is usually applied onto high speed train, and therefore higher running safety requirement is desirable. The influence of semi-active suspension system on safety of vehicles running on straight line and curve line is studied, and the influences of sky hook damping coefficient and system time-delay on operational safety of cars fitted with semiactive suspension system is analyzed. The results show that in vehicles equipped with semi-active suspension system, while the vibration of car body is decreased, the running safety of cars is not affected to any significant degree. As a result, the ride quality is much improved with negligible deterioration of the running safety of cars.

• Korean Journal of Applied Biomechanics
• /
• v.24 no.4
• /
• pp.359-365
• /
• 2014

A study was conducted to investigate the possible effects of fatigue which was resulted from increased running time on the stability during a prolonged run. The purposes of this study were twofold: first, to determine the discrete and non-linear variability of GRF (ground reaction force) components between running times to know the body stability, and second, to determine the pattern between discrete and non-linear variability. Nineteens healthy young adult males served in this study as subjects who ran at their preferred running speed. GRF data for twenty strides were collected at 5, 65, and 125 minutes during run. Variance coefficient and Lyapunov Exponent techniques on the GRF data were used to calculate variability index for each of the running time conditions. There were no difference between discrete variabilities of three components of GRF, but non-linear variability of the Fz component of GRF was decreased by increasing running time (p<.01). No relationship was found between discrete and non-linear variability.

• International Journal of Railway
• /
• v.2 no.4
• /
• pp.147-151
• /
• 2009

Railway vehicles equipped with semi-active suspension system can improve the ride quality of car bodies. Semi-active suspension system is usually applied onto high speed train, and therefore higher running safety requirement is proposed. The influence of semi-active suspension system on safety of vehicles running on straight line and curve line is studied, and the influences of sky hook damping coefficient and system time-delay on operation safety of cars fitted with semiactive suspension system is analyzed. The results show that the vehicles equipped with semi-active suspension system, not only the vibration of car body is decreased, it can also give little influence on running safety of cars, as a result, it will not endanger the running safety of cars.

• Proceedings of the KSR Conference
• /
• 2011.10a
• /
• pp.1881-1887
• /
• 2011

The speed-limit regulation on the turnout is the main cause which hinders the speed-up of conventional lines among many factors. The specification speed for the train which passes the turnout system is lower than that on the general track. In this paper, shape of guard rail of Daegu Metropolitan Transit Corporation was investigated, and the effect of the variation of guard rail length on the running safety of a vehicle was analyzed for the purpose of speed improvement on turnout using the developed analysis method.

• Proceedings of the KIEE Conference
• /
• 2006.10d
• /
• pp.265-267
• /
• 2006

There are various elements that have influence on safety and reliability of high-speed railway vehicles. Among them, mechanical characteristics of traction motors are very important. Therefore, we verified that temperature characteristics have influence on damage and durability of these parts. We designed a measurement system for temperature test, and could measure the temperature of each device by the system. As the result of temperature test, we could confirm that the traction motors on Korean High-Speed Train satisfy the criteria. From this test, we get information of the traction motor about the temperature characteristic during running speed and running time.

• Journal of KSNVE
• /
• v.10 no.4
• /
• pp.636-641
• /
• 2000

KHST(Korea High Speed Train) project plans to design and to build an high speed train. There are noise requirements in passenger room for the standing and running condition, which should be reached. Predicted noise calculated for the standing and running TM5(Motorized car) and TT4(Trailer car) train (v=300 km/h and v=350 km/h) to find out critical areas in or around the train. From the estimation in DWA IfS, actions of noise reduction are proposed to reach the requirements. This paper takes the review of the calculated results in DWA IfS to propose a new design of inner wall.

• Proceedings of the KIEE Conference
• /
• 2015.07a
• /
• pp.737-739
• /
• 2015

In this paper, a novel method of sensorless control scheme is proposed to apply on a single phase hybrid SRM used in high speed operation. The proposed method utilizes beneficially permanent magnet field whose performance is motor parameter independent to estimate the rotor position. Also, the current slope is adopted to complete the sensorless control when the motor running with heavy torque at high speed condition. Through this approach, the adjustable turn on/off position can be achieved without prior knowledge of inductance profile which is always employed by many sensorless schemes. And this paper may offer an available method to do the sensorless control in hybrid SRM used for high speed running.

• Journal of Mechanical Science and Technology
• /
• v.17 no.5
• /
• pp.668-678
• /
• 2003

For the purpose to facilitate development of high-speed spindle units (SUs) running on rolling bearings, we have developed a beam element model, algorithms, and software for computer analysis of thermal characteristics of SUs. The thermal model incorporates a model of heat generation in rolling bearings, a model of heat transfer from bearings, and models for estimation of temperature and temperature deformations of SU elements. We have carried out experimental test and made quantitative evaluation of the effect of operation conditions on friction and thermal characteristics of the SUs of grinding and turning machines of typical structures. It is found out that the operation conditions make stronger effect on SU temperatures when rpm increases. A comparison between the results of analysis and experiment proves their good mutual correspondence and allows us to recommend application of the models and software developed for design and research of high-speed SUs running on rolling bearings.

• 연구논문집
• /
• s.25
• /
• pp.13-22
• /
• 1995

At the running speed higher than 250 km/h, several aerodynamic problems such as the increase of aerodynamic resistance, aerodynamic noise, pressure fluctuation at the tunnel entry, impulsive wave at the tunnel exit bring about the power consumption, deterioration of riding quality, and severe environmental noise. To solve these aerodynamic problems, the flow phenomena around the high speed train have to be analyzed in detail. In this study, the flow around the train is modelled as the 2-dimensional viscous compressible flow and the flow field is calculated numerically for the three different types of geometry and running speed. The aerodynamic drag coefficient and the pressure coefficient are evaluated each case.