• Journal of the Korean Society for Railway
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• v.17 no.1
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• pp.19-27
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• 2014

Urban railway vehicles operate in downtown areas. Due to increases in the number of passengers and changes in the service plans, railway vehicles are expected to operate on sharp curved tracks. However, on these tracks, the running stability of the railway vehicles is significantly decreased and the creepage is increased. Creepage causes the wheel/rail to wear and vibration. Therefore, reducing the creepage helps ensure the running stability and can be beneficial for the environment and cost. In this paper, the longitudinal creepage is analyzed using a railway vehicle model on a sharp curved track. Furthermore, in order to minimize the problems when a railway vehicle runs on a sharp curved track, the characteristics of a bogie are optimized using response optimization.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.9 no.8
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• pp.1716-1721
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• 2005

Conventionally, 2WS is used for vehicle sleeting, which can only steering front wheel. In case of trying to high speed slalom or emergency through this kind of vehicle equipped 2WS, it may occur much of side slip angle. On the other hand, 4WS makes decreasing of side slip angle, outstandingly, so it is possible to support vehicle movement stable. And conventional ABS and TCS can only possible control the longitudinal movement of braking equipment and drive which can only availab to control of longitudinal direction. There after new braking system ESP was developed, which controls both of longitudinal and lateral, with adding of the function of controlling Active Yaw Moment. On this paper, we show about not only designing of improed braking and steering system through establishing of the integrated control system design of 4WS and ESP but also designing of the system contribute to precautious for advanced vehicle stability problem.

• Journal of the Korea Convergence Society
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• v.9 no.10
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• pp.249-255
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• 2018

This paper presents a human-centered control algorithm for personalized autonomous driving based on the integration of inverse time-to-collision and time headway. In order to minimize the sense of difference between driver and autonomous driving, the human-centered control technology is required. Driving characteristics in case that vehicle drives with the preceding vehicle have been analyzed and reflected to the longitudinal control algorithm. The driving characteristics such as acceleration, inverse time-to-collision, time headway have been analyzed for longitudinal control. The control algorithm proposed in this study has been constructed on Matlab/Simulink environment and the performance evaluation has been conducted by using actual driving data.

• Journal of the Korea Computer Graphics Society
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• v.23 no.5
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• pp.57-66
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• 2017

In this paper, we suggest a novel physics-based real-time animation technique for vehicles, and introduce an easy and intuitive animation authoring tool which uses our proposed technique. After a user specifies a trajectory of a virtual car as input, our system produces a more accurate simulation faster than a previous research result. This is achieved by a trajectory splitting method based on directional features and a trajectory library. As a result, the user can create not only a car animation including lane changing and passing, but also a crash animation which is a rarely researched topic. Also, we propose a virtual car structure that approximates a real car's structure for real-time simulation, the resulting animation shows high plausibility such as a small vibration which occurs when the virtual car breaks and a deformation of when a car accident happens.

• Journal of the Korea institute for structural maintenance and inspection
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• v.8 no.1
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• pp.129-138
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• 2004

In this study we determine a dynamic analysis of the existing two-span prestressed concrete box girder bridge subjected to moving vehicle loads using the experimental measurements. The moving loads applied in this paper are classified as general travelling, suddenly brake, continuous travelling, reversely travelling and reversely travelling impact loads for increasing velocities. For each travelling load, we search dynamic behaviors and characteristic in various measuring point of box girder section. In addition, the three-dimensional numerical results analyzed by the developed finite element program using flat shell element with six degrees of freedom per a node are compared with the measured experimental data. Dynamic behaviors caused impact loads by suddenly braking, reversely travelling, are bigger than by general travelling in box girder. Three-dimensional numerical results are better than one-dimensional results.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.19 no.11
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• pp.541-549
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• 2018

This paper deals with the braking dynamic behavior of diesel electric locomotive pulling domestic cargo and passenger vehicles. Friction coefficient, pneumatic pressure, and running resistance affecting the braking system were tested. For the friction coefficient, the Dynamo test was performed with reference to UIC 541-4. The results are analyzed by multivariate regression and the relationship between braking force and ititial velocity is presented. The pneumatic pressure were classified into service braking and emergency braking. In order to reflect the characteristics of the brake valve and piping, the pressure rising over time was measured in the vehicle. In order to reflect the external force acting on the vehicle, we carried out the test of EN 14067-4 and presented the second order polynomial formula on a running resistance. The running resistance test results were compared with other countries. The dynamic behavior of a diesel electric locomotive running on a straight flat track based on vehicle resources, friction coefficient, braking pressure, and running resistance is simulated using the time integration presented in EN 14531-1. The simulation results were compared and verified with the vehicle braking test results. The results of this study can be used to analyze the dynamic braking behavior of a train. Also, it is expected that various parameters affecting braking in vehicle design can be analyzed and used as basic data for braking performance improvement.

• Journal of Korean Society of Transportation
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• v.33 no.4
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• pp.405-416
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• 2015

This paper developed a method analyze drivers' response characteristics using spectral analysis with car following data. Cross-correlation function and cross spectrum are produced by Fourier transform from speed fluctuations of leading vehicle and following vehicle during the designated time ${\tau}$. Based on the analysis data, a process to calculate the reaction time and stimulus-adaption index of following vehicle was developed and 170 cases of field data was applied. It was reported average of 0.654 and 2.091 seconds of stimulus-adaption index and reaction time respectively. In conclusion, the developed indexes might contribute to enhance vehicle control of autonomous vehicle more efficient and safer.

• Journal of the Korean Institute of Gas
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• v.12 no.2
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• pp.7-11
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• 2008

This paper presents the experimental results on the oil leakage characteristics of stem seals depending on the driving distance in LPG vehicle. The increased speeds of the camshaft and oil temperatures do not affect to the oil leakage of the seals because of the low level of driving distances less than 40,000 km. But the increased driving distance over 50,000 km to 100,000 km shows a rapid deteriorating the sealing performance, which may increase the oil leakage through the rubbing surfaces between the poppet valves and stem seals. In this result, the stem seal may be exchanged about the driving distance of 50,000 km to 60,000 km with a currently used stem seal in LPG car. Thus, the stem seal for a poppet valve should be resigned for the increased durability and long life.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.2 no.4
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• pp.603-610
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• 1998

The purpose of this paper is to describe how the characteristics of the movement of cars can be modeled with computers. For this, we use Matlab and simulate the characteristics of the cruise-speed at which the car is driven using the Fuzzy PID controller. The model of the car is designed by M-S(Matlab-Simulink) and each parameter of PID is estimated automatically by the Fuzzy controller. The simulation of the car is carried out on straight base tracks, and then this is compared and analyzed with the simple Fuzzy controller and the simple PID controller.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 1990.10a
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• pp.143-147
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• 1990

자동차는 주행시에 노면가진으로 인하여 진동을 받게 되는 데 이러한 진동 은 운전자의 승차감을 저하시킬 뿐만 아니라 화물과 차량 부품을 파손시키 는 원인이 되기도 한다. 노면가진력은 주로 현가장치를 통하여 차량에 전달 되어 차량의 진동을 유발하게 되므로 승차감을 향상시키려면 노면가진을 효 과적으로 차단할 수 있도록 현가장치를 설계하여야 한다. 이를 위하여 본 논 문에서는 차량을 현가장치의 형식에 따라 3가지 종류로 구분한 다음 각각을 12자유도로 모델링하여 노면이 불규칙(random)한 도로를 주행할 때의 승용 차의 진동을 해석하고, 현가스프링의 강성과 쇼크 압소바의 감쇠 값이 자체 수직 가속도 유효치(rms value)와 현가장치 유효행정(rms stroke length)에 미치는 영향을 분석하였다. 차량의 운동방정식은 현가장치의 비선형 특성을 고려하였기 때문에 미소 각 운동의 가정에도 불구하고 비선형 방정식이 된 다. 운동 방정식의 해는 4차 Runge-Kutta 적분법을 사용하여 수치해석으로 구하였다.