• Journal of Auto-vehicle Safety Association
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• v.11 no.3
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• pp.37-42
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• 2019

This paper presents an autonomous acceleration planning algorithm for pedestrian collision avoidance at urban. Various scenarios between pedestrians and a vehicle are designed to maneuver the planning algorithm. To simulate the scenarios, we analyze pedestrian's behavior and identify limitations of fusion sensors, lidar and vision camera. Acceleration is optimally determined by considering TTC (Time To Collision) and pedestrian's intention. Pedestrian's crossing intention is estimated for quick control decision to minimize full-braking situation, based on their velocity and position change. Feasibility of the proposed algorithm is verified by simulations using Carsim and Simulink, and comparisons with actual driving data.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.37 no.11
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• pp.1371-1377
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• 2013

In this analysis, a method is presented to calculate the critical speed of a railway vehicle by using a multibody dynamic model. The contact conditions and contact forces between the wheel and the rail are formularized for the wheelset model. This is combined with the bogie model to obtain a multibody dynamic model of a railway vehicle with constraint conditions. First-order linear dynamic equations with independent coordinates are derived from the constraint equations and dynamic equations of railway vehicles using the QR decomposition method. Critical speeds are calculated for the wheelset and bogie dynamic models through an eigenvalue analysis. The influences of the design parameters on the critical speed are presented.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.36 no.9
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• pp.1003-1008
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• 2012

The paper presents an Experimental Vehicle Model (EVM), that utilizes the kinematic characteristics of suspensions from SPMD test data. The relative displacement and orientation of a wheel with respect to the body are represented as a function of the vertical displacement of the wheel. The equations of motion of the vehicle are formulated in terms of local coordinates that do not require coordinate transformation, which improves the efficiency of dynamic analysis. The EOM was modularized for each suspension model, and a $6{\times}6$ vehicle model was obtained by combining six suspensions. The analysis results were compared with ADAMS to verify the accuracy of the EVM. This study also verifies the feasibility of real-time simulation with the developed EVM. For a vehicle simulation for 1 ms, the real simulation time required within 20% of the prescribed time. This result shows that the EVM meets the real-time simulation requirements.

• Journal of the Korean Society for Railway
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• v.12 no.1
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• pp.65-71
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• 2009

The pressure transient inside the passenger cabin of high-speed train has been assessed using computational fluid dynamics (CFD) based on the axi-symmetric Navier-Stokes equation. The pressure change inside a train have been calculated using first order difference approximation based on a linear equation between the pressure change ratio inside a train and the pressure difference of inside and outside of the train. The numerical results show that the pressure change inside the new Korean high-seed train passing through a tunnel of Seoul-Busan high-speed line at the speed of 330km/h satisfied well the Korean regulation for pressure change inside a passenger cabin if the train is satisfying the train specification for airtightness required by the regulation.

• Proceedings of the KIEE Conference
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• 2008.04a
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• pp.230-231
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• 2008

본 논문은 KRRI 전륜 조향 차량의 횡 방향 동역학 모델링에 대한 내용을 기술한다. 이 차량은 굴절버스 형태를 갖고 모든 차륜의 조항이 가능하며 트레일러와 트랙터의 후륜이 독립적으로 구동 가능한 시스템을 갖고 있다. 이 시스템의 모델링은 비선형 동역학 방정식을 유도하고 선형화 한 뒤 횡 방향 동역학 모델만을 분리해서 최종적으로 횡 방향 선형 동역학 모델을 유도하는 과정을 거친다. 마지막으로 시뮬레이션을 통해 선형 모델을 검증한다.

• Journal of Auto-vehicle Safety Association
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• v.14 no.2
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• pp.7-13
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• 2022

This paper presents a yaw moment control based on estimated mass for manual-shift commercial vehicles. In yaw moment controller, parameter uncertantiy of vehicle mass is important because the desired yaw moment depends on vehicle parameter. However, in the case of commercial vehicle, the weight of the loaded vehicle is more than twice as much as compared to the unloaded vehicle. The proposed algorithm estimates the vehicle mass by using the longitudinal dynamic and gear shifting characteristics. The estimated mass is used to adaptively modify the vehicle parameters. In addition, this paper estimates the chamber pressure of a pneumatic brake and generates the target yaw moment through on/off valve control. MATLAB/Simulink and Trucksim were performed under sine with dwell test. The results demonstrate that the proposed algorithm improves the lateral and rollover stability.

• Proceedings of the Korea Information Processing Society Conference
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• 2023.11a
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• pp.880-881
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• 2023

본 연구는 차량 동역학이 적용된 자율주행 시뮬레이터에서 구현된 차량의 거동이 실제 차량과 유사한지 검증하는 것이다. 이를 위해 실제 차량모델에 외력을 가할 수 있는 기구를 개발하여 데이터를 획득하고 분석하고자 한다. 시뮬레이터에서 구현된 차량과 유사한 서스펜션 구조를 가진 차량 모델을 만들고 센서를 달아 차량의 운동 모델을 모사했으며, 캠과 감속기어를 활용해 외력을 모사하기 위한 기구를 제작하였다.

• Journal of the KSME
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• v.43 no.8
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• pp.57-63
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• 2003

2002년 한 해 동안 동역학 및 제어 분야의 연구 동향을 동역학, 진동, 계측, 제어, 기구학, 로봇공학, 차량공학 등으로 나누어 각 분야에 대하여 정리하였다.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2008.04a
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• pp.964-969
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• 2008

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2004.05a
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• pp.207-207
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• 2004

고속철도의 개통이 가까워지면서 사회적 관심이 고조되고 있으며, 특히 안전과 환경의 문제가 주요한 관심사로 대두되고 있다. 특히 공기역학적 관점에서 볼 때 300km/h의 고속에서는 지금까지 국내에서 경험하지 못한 여러 가지 문제점들이 나타나리라 예상되고 있으며, 그 중에서도 승강장에 대기증인 승객 또는 보행자가 열차 통과 시에 느끼는 불쾌감과 위험에 대한 조사와 대책이 필요한 시점이다.(중략)