• The Transactions of the Korean Institute of Power Electronics
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• v.6 no.3
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• pp.299-306
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• 2001

It is one of the most effective methods for performance improvement of electric railway vehicle to make better the wheel-rail adhesion character. In order to research adhesion character, adhesion system is developed. The experiment system makes it possible to change various adhesion parameters. This paper studied to restrain vibration of slip speed using torque control gy means of slip speed.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.60 no.10
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• pp.1903-1914
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• 2011

In this paper, we propose vehicle running characteristic simulator. The developed simulator is configured by two induction motors which are directly coupled with each other. One motor is to simulate the vehicle drive and another motor is to simulate the vehicle dynamic load including running resistance, gradient resistance and adhesive characteristics between rail and wheel. The running characteristics of vehicle are modeled by numerical formulas. These are programed by software of embedded controller. Thus, it is possible to change several running characteristics during the running test freely and instantly. To evaluate the feasibility of the simulator, the experiments on slip and adhesion coefficient are performed. Additionally the adhesion control and speed control of vehicle are tested with simulator. Experimental results show that the simulator can produce the driving characteristics similar to the vehicle system.

• Proceedings of the KSR Conference
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• 2004.10a
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• pp.640-645
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• 2004

In this thesis, the impact analysis for the shunting procedure using the dynamic buffer characteristics of the coupler was developed. In this study, each car was modeled as one dimensional element by using the equivalent system. After the impact, the slip exists only between wheel and rail in the braked trainset. For this analysis the analysis code named the POTAS-MSM (Power Transmission Analysis Software Multi Slip Mechanism) which was developed for the numerical analysis of dynamic system is developed. The validation of this analysis was proven by comparing the numerical results with the results of world-famous S company which is located in Europe.

• Journal of the Korean Society for Precision Engineering
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• v.18 no.3
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• pp.99-106
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• 2001

Model trains should have very similar motion characteristics to real trains in order to provide realistic feeling to their operators. Main purpose of dynamic analysis of model trains is to predict velocities in straight and circular tracks and estimate stopping distance after power shut off. Equations of motion for a model train are derived that relates velocity, traction, rolling resistance, and pulling force. Also, energy equations for calculating stopping distance after power shut off are derived. Experiments with model trains are preformed to measure velocity, rolling resistance, slip, and stopping distance. The results are compared with the prediction based on the equations of motion, and they showed good agreement. It can be concluded that the prediction is more accurate when the slip between wheel and rail is accounted for. The analysis procedures can be applied to determining various design factors in model trains.

• Journal of the Korean Society of Manufacturing Technology Engineers
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• v.21 no.6
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• pp.968-975
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• 2012

ABS(Anti-skid Brake System) had been developed on purpose of most effect at breaking in limited runway. An aircraft has a large amount of kinetic energy on landing. When the brakes are applied, the kinetic energy of the aircraft is dissipated as heat energy in the brake disks between the tire and the ground. The optimum value of the slip during braking is the value at the maximum coefficient of friction. An anti-skid system should maintain the brake torque at a level corresponding to this optimum value of slip. This system is electric control system for brake control valve at effective control to prevent slip and wheel speed or speed ratio. In this study we measured the thickness of the carbon disk before and after to find its wear and it shows that carbon disk brake has higher stiffness and strength than metal disk at high temperature. In addition, thermal structural stability and appropriate frictional coefficient of the carbon disk brake prove its possible substitution of metal disk brake.

• Journal of the Korean Society for Railway
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• v.11 no.2
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• pp.176-181
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• 2008

This paper presents results from experimental analysis of a friction-driven wheel responsible for generating wheel squeal noise. Squeal noise generating mechanism has been examined under the laboratory condition by the model rig on a small scale. Creep characteristics and squeal noise were observed by changing the possible variables, such as relative velocities and friction coefficients in time- and frequency-domain.

• International Journal of Automotive Technology
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• v.7 no.7
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• pp.803-812
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• 2006

In order to reduce the negative effects of dynamic coupling among vehicle subsystems and improve the handling performance of vehicle under severe driving conditions, a vehicle chassis control integration approach based on a main-loop and servo-loop structure is proposed. In the main-loop, in order to achieve satisfactory longitudinal, lateral and yaw response, a sliding mode controller is used to calculate the desired longitudinal, lateral forces and yaw moment of the vehicle; and in the servo-loop, a nonlinear optimizing method is adopted to compute the optimal control inputs, i.e. wheel control torques and active steering angles, and thus distributes the forces and moment to four tire/road contact patches. Simulation results indicate that significant improvement in vehicle handling and stability can be expected from the proposed chassis control integration.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2005.06a
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• pp.383-386
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• 2005

An integrated analytical model which should have essential dynamics on the longitudinal railway vehicle is developed. The model consists of translational movement, rotational movement, brake actuator, adhesion force between rail and wheel, and brake friction force between wheel and pad. Thus, during the deceleration for stopping, a feedback controller controlling the brake cylinder pressure is designed to improve ride quality and to release friction problems. Through the developed model, the feasibility of controlling the cylinder pressure is verified for the better performances during braking.

• Proceedings of the KIEE Conference
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• 2000.07d
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• pp.2561-2563
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• 2000

In this paper, a mathematical vehicle model, the braking force control parameters, the wheel control logic, and vehicle control strategy are presented, in order to analyze the dynamic characteristics of a vehicle equipped with ABS(Antilock Brake System). The full vehicle dynamics model is constructed with sprung mass, brake system, and wheels to verify control algorithms. The valve control algorithms are designed with the wheel accelerations and slip ratio take into consideration. Theses algorithms are applied to the front and rear wheels independently. Simulation is performed under the wet road condition at initial braking speed of 60 [km/h].

• Journal of the Korean Society of Mechanical Technology
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• v.13 no.2
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• pp.71-78
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• 2011

A kart is a vehicle without the suspension system and the differential gear. The kart frame as an elastic body plays the role of a spring. By the cornering of a kart, rolling, pitching and twisting motions are induced in the kart frame. Also the slip or noncontact of the wheel and a permanent deformation of the kart frame can be induced. In order to examine closely this phenomenon, measurement on height-displacements with various sensors and tracking system and analysis on the kart frame twisting characteristics with the rolling and pitching angle are needed. According to the measurement result, while driving in a curve at high speed the kart frame is quite twisted. Analysis on the measurement results shows that a kart used primarily in high speed requires a frame with low torsional stiffness and a frame material with high tensile strength and large elongation.