• Journal of the Earthquake Engineering Society of Korea
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• v.15 no.3
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• pp.1-9
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• 2011

The purpose of this study is to examine the dynamic characteristics of low, medium and high speed Maglev trains and guideways through dynamic interaction analysis. The coupled dynamic equations of motion for a vehicle of 10-dof and the associated guideway girders are developed by superposing vibration modes of the girder itself. The controller used in the UTM-01 Maglev vehicle is adopted to control the air gap between the bogie and guideway in this study. The effect of roughness, the guideway deflection-ratio and vehicle speed on the dynamic response of the maglev vehicle and guideway are then investigated using the 4th Runge-Kutta method. From the numerical simulation, it is found that the air gap increases with an increase of vehicle speed and the roughness condition. In particular, the dynamic magnification factor of the guideway girder is small at low and medium speeds, but the factor is noticeable at super-high speeds.

• Journal of Auto-vehicle Safety Association
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• v.10 no.2
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• pp.6-12
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• 2018

Optimized section shape of aluminum bumper backbeam for enhancing the front high speed crashworthiness was investigated. Front body analysis model of a convertible vehicle was built up and parameter studies were carried out with changing the inner rib shape and the section thickness distribution. First an inner rib shape displaying most efficient structural performance was selected. Next, for the selected section the effect of section thickness combination was examined. Also, a light weighed backbeam section displaying crash performance over the current design was suggested. Finally RCAR front low speed impact analyses were carried out for the optimized models.

• Transactions of the Korean Society of Automotive Engineers
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• v.12 no.4
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• pp.191-197
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• 2004

This paper presents experimental results for human drivers' driving patterns and an Adaptive Cruise Control(ACC) strategy. Analyses have shown that female drivers' driving characteristic values such as time-gap and minimum clearance are larger than those of male drivers'. Human drivers tend to have more clearance margins at high speed than at low speed. At low speed, drivers are much more sensitive to the desired clearance than at high speed. A multi-vehicle detection method is presented to improve ride quality of an ACC. Simulation results have shown that the proposed ACC can provide superior performance compared to the ACC strategy which uses a single-vehicle detection method.

• Proceedings of the KSR Conference
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• 2011.10a
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• pp.107-118
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• 2011

This paper performs flow analysis of ultra-high speed vehicle inside the long distance tunnel. One and three dimensional hybrid mesh was used for describing moving motion and flow analysis of an vehicle inside a long distance tunnel which over 20 km. Flow analysis and aerodynamic drag measuring were performed by three dimensional mesh: around vehicle, and pressure waves of a tunnel was measured by one dimensional mesh: the other region where rare changing of flow pattern.

• Journal of the Korean Society for Precision Engineering
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• v.31 no.9
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• pp.759-764
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• 2014

Lateral force of wheel is important parameter when we evaluate the safety of a railway vehicle on curved track. The lateral force of wheel is influenced by the steering performance of wheelsets. Generally, in passive type vehicles, the steering performance of wheelsets is influenced by the parameters like primary spring stiffness, wheel base, conicity of the wheel profile, etc. But, the steering performance of passive type vehicle has its limit. To overcome the limit of the steering performance of passive type vehicle, active steering technology is being developed. In this paper, we analyze the lateral force of wheel and the safety of the railway vehicle on curved track by adopting the active steering technology. As results of dynamic analysis for vehicle model equipped with active steering system, the lateral force of wheel is reduced and the safety is improved remarkably.

• International Journal of Automotive Technology
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• v.6 no.4
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• pp.351-357
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• 2005

Development of a real-time simulation model for high-speed and multibody tracked vehicles is difficult because they involve hundreds of highly nonlinear equations. In the development of a reliable tracked vehicle model for real-time simulation, it is helpful to use an off-line tracked vehicle model developed by considering all the degrees of freedom of each element. This paper presents a step-by-step procedure for the development of a real-time simulation model based on the off-line tracked vehicle model. The road input data, Profile IV, is used for the real time simulation and simulation results are compared with vehicle test results obtained in the military test field. It is noted that the simulation results are quite close to the test results.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2005.06a
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• pp.378-382
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• 2005

The opening of high speed railway upgraded our land transportation speed limit, causing lots of changes including living and culture and also paving the way for stepping up the railway technology. However, it is also true that we had a limit to adopt the existing railway system structured for 150km/h to the new structure requiring a higher speed of approximate 300km/h due to technological, based on the time and experience. More importantly, heading toward a step of operating such a high speed railway system, it has been practically and quickly proposed that the railway needs high speed railway engineering, maintenance technology of parts of the vehicles to have a stable maintenance foundation and localization of major parts. Therefore, this study was intended to research the actual displacement characteristics in runningg on an actual track for the purpose of developing the protective and maintenance technology of springs and dampers, which are core parts among suspension elements of a high speed railway vehicle. For this, it was researched the actual vehicle test and its interpretation centered on primary spring, which is used for the suspension system of a bogie, body-body dampers and body-bogie yaw damper. Also, to analyze the displacement characteristics of suspension system in the actual conditions of high speed railway vehicles, a vehicle‘s dynamic characteristics was analyzed and interpreted. At the same time, a tester for measuring the actual displacement of such suspension elements was designed and attached to actual vehicles, to measure the displacements that occur in running it on the Seoul-Busan line, one of major lines serviced by KTX. The displacement data gained from the test with actual vehicles was analyzed for its displacement distribution depending on the service sections and frequency, with which the valuable data necessary for any potential breakdown or maintenance in the future could be obtained.

• Journal of Korea Multimedia Society
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• v.24 no.12
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• pp.1632-1640
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• 2021

In order to improve target tracking performance of the conventional electro-optical tracking system (EOTS) in the high speed and high maneuvering vehicle, an EOTS navigation algorithm is proposed, in which an inertial measurement unit(IMU) is included and navigation results of the vehicle are used. The proposed algorithm integrates vehicle's navigation results and the IMU and the time-delay and the scale factor errors are augmented into the integrated Kalman filter. In order to evaluate the proposed navigation algorithm, a land vehicle navigation experiments were performed a navigation grade navigation system, TALIN4000 and a tactical grade IMU, LN-200 and a equipment for roll motion were loaded on the land vehicle. The performance evaluation results show that the proposed algorithm effecting works in high maneuvering environment and for the time-delay.

• Journal of Electrical Engineering and Technology
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• v.6 no.1
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• pp.81-85
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• 2011

The end effect of a linear induction motor (LIM) has been known for several decades, especially in high speed operation. The exit part of the primary is not dealt as extensively as the entry part because of its minor effect. However, the exit part is one of the keys to weaken the dolphin effect, which occurs in high speed operation. In this paper, the concept of the virtual primary core is introduced, and chamfering of the primary outlet teeth is proposed to minimize the longitudinal end effect at the exit zone. For this, LIM for the high-speed train is designed and analyzed by using finite element method. Results confirm that chamfering can improve thrust performance effectively.

• International Journal of Precision Engineering and Manufacturing
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• v.3 no.3
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• pp.21-27
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• 2002

In this paper, a simple test rig of high-speed crash for the front members of vehicles was developed for the improvement of crashworthiness of vehicle's side rail. The cart hanging the specimen is accelerated up to 35 mph by the traction wire and by the force of freely dropping weight and 1:3 accelerating pulleys. The cart with shock absorbers travels on the rail roads, so it does not transfer any additional vibration to the specimen. In order to measure the energy absorbed by the specimen when it collapse to the wall and during it deform, the two strain gage type load cells are used at the wall place. The test rig rated good to test the specimen like a side rail of vehicle as developing the vehicle's structures in the early design stage.