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하윤석,이명수,Ha, Yunsok,Yi, Myungsu 대한용접접합학회 2015 대한용접·접합학회지 Vol.33 No.3
A very large shell-structure built in shipyards like ship hulls or offshore structures are joined by welding through full process. As the welding contains a high thermal cycle at a local area, the welded structures should be distorted unavoidably. Because a distorted ship block should be revised to the designed value before the next stage, the ability to predict and to control the weld distortion is an accuracy level of the yard itself. Despite the ship block size, several present thermal distortion methodologies can deal those sizes, but it is a different story to deal full ship size model. Even a fully constructed ship hull not remaining any welding can have an accuracy issue like outfitting installation problems. Any present thermal distortion methodology cannot accept this size for its recommended element size and the number. The ordinary welding breadth at erection stage is about 20~40 mm. It can hardly be a good choice to make finite element model of these sizes considering human effort and computational environment. The finite element model for structure analysis of a ship hull is prepared at front-end engineering design stage which is the first process of the project. The element size of the model is as fine as the longitudinal space, and it is not proper to obtain a weld distortion at the erection stage. In this study, a methodology is suggested that a weldment can be shrunk at original place instead of using structural finite element model. We cut the original shell elements at erection weld-line and put truss elements between the edges of cut elements for weld shrinkage. Additional truss elements are used to facsimile transverse weld shrinkage which cannot be from the weld-line truss element shrink. They attach to weld-line truss element like twigs from barks. The capacity of developed elements is verified through an accuracy check of erection process of a container vessel at the apt. hull. It can be a useful tool for verifying a centering accuracy after renew and for block-separating planning considering accuracy.
레이더, 비전, 라이더 융합 기반 자율주행 환경 인지 센서 고장 진단
최승리,정용환,이명수,이경수,Choi, Seungrhi,Jeong, Yonghwan,Lee, Myungsu,Yi, Kyongsu 한국자동차안전학회 2017 자동차안전학회지 Vol.9 No.4
For automated vehicles, the integrity and fault tolerance of environment perception sensor have been an important issue. This paper presents radar, vision, lidar(laser radar) fusion-based fault detection algorithm for autonomous vehicles. In this paper, characteristics of each sensor are shown. And the error of states of moving targets estimated by each sensor is analyzed to present the method to detect fault of environment sensors by characteristic of this error. Each estimation of moving targets isperformed by EKF/IMM method. To guarantee the reliability of fault detection algorithm of environment sensor, various driving data in several types of road is analyzed.
채흥석,정용환,이명수,신재곤,이경수,Chae, Heungseok,Jeong, Yonghwan,Lee, Myungsu,Shin, Jaekon,Yi, Kyongsu 한국자동차안전학회 2017 자동차안전학회지 Vol.9 No.1
Regulation for the testing and operation of automated vehicles on public roadways has been recently developed all over the world. For example, the licensing standards and the evaluation technology for automated vehicles have been proposed in California, Nevada and EU. But specific safety evaluation scenarios for automated vehicles have not been proposed yet. This paper presents safety evaluation scenarios for extraordinary service permission of automated vehicles on highways. A total of seven scenarios are selected in consideration of safety priority and real traffic situation. Six scenarios are relevant with lane keeping and one scenario is relevant with lane change. All scenarios are developed based on existing ADAS evaluation scenarios and repeated simulation of automated vehicle algorithm. Safety evaluation factors as well as scenarios are developed. The safety factors are based on existing ADAS ISO requirements, ADAS safety factors and current traffic regulations. For the scenarios, a hunter vehicle is needed in addition to automated vehicle evaluated. The hunter vehicle performs multiple roles like preceding vehicle, cut-in vehicle and so on. The hunter vehicle is also automated vehicle equipped with high performance GPS, radar and Lidar. All the scenarios can be implemented by driving a lap on a KATRI ITS test track. These scenarios and safety evaluation factors are investigated via both a computer simulation and an experimental vehicle test on the test track. The experimental vehicle test was conducted with two automated vehicles, which are the evaluated vehicle and the hunter vehicle.
전동식 조향 장치의 성능 평가를 위한 신경 근육계 기반 운전자 모델 개발
이성현,이동필,이재풍,채흥석,이명수,이경수,Lee, Sunghyun,Lee, Dongpil,Lee, Jaepoong,Chae, Heungseok,Lee, Myungsu,Yi, Kyongsu 한국자동차안전학회 2017 자동차안전학회지 Vol.9 No.3
This paper presents a lateral driver model with neuromuscular system to evaluate the performance of electric power steering (EPS). Output of most previously developed driver models is steering angle. However, in order to evaluate EPS system, driver model which results in steering torque output is needed. The proposed lateral driver model mainly consists of 2 parts: desired steering angle calculation and conversion of steering angle into steering torque. Desired steering angle calculation part results in steering angle to track desired yaw rate for path tracking. Conversion of steering angle into torque is consideration with neuromuscular system. The proposed driver model is investigated via actual driving data. Compared to other algorithms, the proposed algorithm shows similar pattern of steering angle with human driver. The proposed driver can be utilized to efficiently evaluate EPS system in simulation level.
고속도로에서의 자율주행 알고리즘 개발 및 평가를 위한 다차량 시뮬레이션 환경 개발
이호준,정용환,민경찬,이명수,신재곤,이경수,Lee, Hojoon,Jeong, Yonghwan,Min, Kyongchan,Lee, Myungsu,Shin, Jae Kon,Yi, Kyongsu 한국자동차안전학회 2016 자동차안전학회지 Vol.8 No.4
Since real road experiments have many restrictions, a multi-vehicle traffic simulator can be an effective tool to develop and evaluate fully automated driving systems. This paper presents multi-vehicle environment simulation tool to develop and evaluate motorway automated driving systems. The proposed simulation tool consists of following two main parts: surrounding vehicle model and environment sensor model. The surrounding vehicle model is designed to quickly generate rational complex traffic situations of motorway. The environment sensor model depicts uncertainty of environment sensor. As a result, various traffic situations with uncertainty of environment sensor can be proposed by the multi-vehicle environment simulation tool. An application to automated driving system has been conducted. A lane changing algorithm is evaluated by performance indexes from the multi-vehicle environment simulation tool.
채흥석(Heongseok Chae),정용환(Yonghwan Jeong),이명수(Myungsu Lee),민경찬(Kyongchan Min),이경수(Kyongsu Yi) 대한기계학회 2015 대한기계학회 춘추학술대회 Vol.2015 No.11
Regulation for the testing and operation of automated vehicles on public roadways has been recently developed all over the world. For example, the licensing standards for autonomous vehicles have been proposed in California and Nevada. However, safety performance evaluation scenarios for automated vehicles have not been proposed yet. It is important to comprehensively evaluate the safety performance of automated vehicles before they are produced and deployed. This paper presents lane change evaluation scenario of automated vehicles. Because lane change is frequently happened in driving situation, lane change evaluation is crucial. The scenario evaluates safety of automated vehicles changing lane, utilizing target vehicle placed on rear-side (next lane) of automated vehicles. The target vehicle is equipped with adaptive cruise control and auto emergency braking based on human driver data. Safety evaluation factors in lane change situation are also developed. This scenario is investigated via computer simulation.
고속도로 합류점 주행을 위한 강건 모델 예측 기법 기반 자율주행 차선 변경 알고리즘 개발
채흥석(Heongseok Chae),정용환(Yonghwan Jeong),민경찬(Kyongchan Min),이명수(Myungsu Lee),이경수(Kyongsu Yi) 대한기계학회 2017 大韓機械學會論文集A Vol.41 No.7
본 논문에서는 고속도로의 합류지점 상황에서 자율주행을 위한 운전 모드 결정 알고리즘의 개발 및 평가를 진행하였다. 합류 상황을 위한 자율주행 알고리즘 개발에 있어 적절하게 합류를 결정하는 운전 모드 결정이 필수적이다. 운전자 모드는 총 2가지로 차선 유지, 차선 변경(합류)이다. 합류 모드 결정은 주변 차량의 정보 및 합류 차선에 남은 거리를 기반으로 결정된다. 합류 모드 결정 알고리즘에서는 합류 가능 여부를 판단하고 합류가 가능할 때, 안전하고 빠르게 합류하기 위한 최적의 위치를 찾는다. 안전 주행 영역은 주변 차량의 정보 및 주행 모드를 기반으로 정의된다. 안전 주행 영역으로 자율주행차량을 유지하기 위한 조향각과 종방향 가속도를 얻기 위해 여러 제한 조건이 더해진 강건 모델 예측기법이 사용되었다. 본 논문에서 제안된 알고리즘은 컴퓨터 시뮬레이션을 이용해 검증되었다. This paper describes the design and evaluation of a driving mode decision algorithm for automated driving for merge situations on highways. For the development of a highly automated driving control algorithm for merge situations, the driving mode decision is crucial for merging appropriately. There are two driving modes: lane keeping and lane changing (merging). The merge mode decision is determined based on the state of the surrounding vehicles and the remaining length of the merge lane. In the merge mode decision algorithm, merge possibility and the desired merge position are decided to change the lane safely and quickly. A safety driving envelope is defined based on the desired driving mode using the information on the surrounding vehicles" behaviors. To obtain the desired steering angle and longitudinal acceleration for maintaining the subject vehicle in the safe driving envelope, a motion planning controller is designed using model predictive control (MPC), with constraints that are decided considering the vehicle dynamics, safe driving envelope, and actuator limit. The proposed control algorithm has been evaluated via computer simulation studies.