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An Information Fusion-based Vision System for an Autonomous Vehicle
Chulhoon Jang,Minchae Lee,Minkwang Lee,Myoungho Sunwoo 한국자동차공학회 2012 한국자동차공학회 학술대회 및 전시회 Vol.2012 No.11
This paper presents an information fusion-based vision system for an autonomous vehicle. To perceive road environments, the autonomous vehicle uses multiple sensors such as cameras, laser radar sensors, global positioning system (GPS), and in-vehicle sensors. The cameras, one of the multiple sensors, are used for object detection by means of color segmentation, multi-scaled template matching, and AdaBoost algorithm. However, since the cameras are influenced by outdoor conditions such as sudden illumination changes and shadows, detection performance cannot be guaranteed. To overcome the problem, the information fusion is applied using the multiple sensors. The information fusion-based vision system performs the object detection with low false positives and fast computation time. Finally, the proposed approach is validated through on-the-road experiments with various environmental conditions.
엔진 Cover류 방사 소음 해석 기술 개발 및 구조적 개선 설계안 도출
이철훈(Chulhoon Lee),김광수(Kwangsoo Kim),오종민(Jongmin Oh),임규운(Gyuun Im) 대한기계학회 2016 대한기계학회 춘추학술대회 Vol.2016 No.12
Recently, exhaust regulations have intensified due to the global warming and air pollution problems. For this reason, the research is being done competitively to develop a higher specific power engine and fuel efficiency engine by weight reduction and engine down-sizing. Although these weight reduction and high power engine development trend is a disadvantage for a NVH performance of the engine, NVH characteristic may be an important performance index to ensure the competitiveness of the product with an increase of customer demand for the noise and vibration performance. These days, CAE analysis technique has been developed actively to predict the NVH performance in the early stage of product development and our company also is studying to predict NVH performance of the engine by using CAE analysis technology by continuously. In this paper, the analysis process for the structural borne noise of the engine covers is developed as one of the NVH analysis and analytical DB is built by performing an assessment of the production model. Also, noise performance of the engine TGC Cover is evaluated by using the analysis process, and structural improved design is recommended based on the analysis results in the development stage.
맥퍼슨 현가 장치를 가진 차량의 승차감 개선을 위한 SRS 해석 및 Design Study
이철훈(Chulhoon Lee),최진호(Jinho Choi) 한국자동차공학회 2007 한국자동차공학회 춘 추계 학술대회 논문집 Vol.- No.-
This paper describes the analysis and design study for improving the Smooth Road Shake (SRS) performance which is one of the most important ride metrics in modem vehicles. The SRS is composed of the steering wheel and floor pan vibrations caused by tire imbalance forces. This study focuses on the steering wheel torsional vibration since the floor pan longitudinal and vertical vibrations are much smaller than the torsional vibration. We performed the fundamental dynamic simulation of SRS by using ADAMS solver based on Motionview with in-house templates. We showed the validity of our SRS model through the comparison of a simulation result with a production vehicle's result. Based on the validated model, we performed design study, and provided design guidelines for enhancing the SRS performance.
무인 굴착기 버츄얼 검증을 위한 자율 작업 시뮬레이션 기술 개발
이철훈(Chulhoon Lee),이제필(Jepil Lee),박흥근(Heungkeun Park),김창묵(Changmook Kim),김동목(Dongmok Kim) 한국자동차공학회 2020 한국자동차공학회 학술대회 및 전시회 Vol.2020 No.11
In addition to the recent development of autonomous vehicles, technologies for automation and unmanned construction equipment are being actively developed in order to increase work efficiency in the field of construction site as well as solve the problem of lack of skilled workers in construction equipment operation. Doosan Infracore is actively developing unmanned/automated equipment and site management solution called X-center as shown in Concept-X demonstrations in 2019. As part of this solution development, we are also developing a simulation technology for virtual verification of autonomous equipment. The unmanned excavator recognizes the work terrain and the surrounding environment of the equipment from the results sensed by Lidar and SVC (Stereo Vision Camera), and trajectory planner controller generates the work command of the excavator according to the work mode such as digging and loading, trenching and grading. Since the automated work is carried out in several stages and the system configuration is complicated, virtual verification through simulation before the actual vehicle test can increase the development efficiency and product reliability. In this paper, we developed the simulation technology and the process for autonomous Excavator by coupling perception system, trajectory planner controller, vehicle dynamics model, and virtual sensor and terrain.
Re-Plannable Automated Parking System With a Standalone Around View Monitor for Narrow Parking Lots
Jang, Chulhoon,Kim, Chansoo,Lee, Seongjin,Kim, Seokwon,Lee, Sumyeong,Sunwoo, Myoungho IEEE 2020 IEEE transactions on intelligent transportation sy Vol.21 No.2
<P>An automated parking system allows drivers to park cars free of stress and collisions in parking lots. Most commercial systems use ultrasonic sensors and require a scanning process to search for a vacant parking space between two adjacent vehicles. If automated parking fails, drivers must return to the initial position for further scanning or take the steering wheel to complete the remaining parking procedure. To improve such limitations, we propose a re-plannable automated parking system with a standalone around view monitor. The proposed system can constantly reflect several errors and risks of perception, positioning, and control in real-life situations, and then re-generate the parking path to improve the parking precision and avoid any collisions. To realize this automated parking system, we propose a new system architecture and introduce four core modules: environmental perception, precise positioning, parking path planning, and vehicle control. In our experiments, we evaluated the system in narrow parking lots with a perpendicular parking space defined as <TEX>$2.1 \times 5.0$</TEX> m. The proposed system successfully performed reverse automated parking with a lateral error of 0.049 m, a longitudinal error of 0.249 m, and a heading error of 0.468°.</P>
굴삭기 선회 디바이스 기어의 Case Crushing 강도 평가 기술 개발 및 설계 최적화
이철훈(Chulhoon Lee),성두현(Doohyun Sung),김광수(Kwangsoo Kim),김경근(Kyeongkeun Kim),임규운(Gyuun Im),박흥근(Heungkeun Park) 한국자동차공학회 2018 한국자동차공학회 부문종합 학술대회 Vol.2018 No.6
Case Crushing failure mode may occur in hardened gears that are subjected to large torque, such as excavator swing device pinions and swing bearing gears. In Case Crushing failure mode, the crack is generated at case core boundary in hardened gears, unlike pitting or bending fatigue which is general gear failure modes. In this paper, the Case Crushing strength analysis methodology was developed and design optimization was performed to improve Case Crushing strength for large size excavator swing bearing gear. For more accurate result, the swing device system was modeled with considering the influence of pinion shaft deformation, roller bearing stiffness, and gear lead slope that is one of the micro geometry. The gear lead slope was optimized by using developed detail analysis model under various swing torque condition.
초기 개발 차량의 승차감 및 조정안정성 향상을 위한 현가장치 SDF 분석에 관한 연구
이철훈(Chulhoon Lee),최진호(Jinho Choi) 한국자동차공학회 2005 한국자동차공학회 춘 추계 학술대회 논문집 Vol.2005 No.11_2
In order to develop a competitive modern vehicle with high quality, major big companies have tried to aggressively introduce virtual engineering technology based on state-of-the-art computer-aided engineering(CAE). This paper deals with a simulation-based design study of suspension system in the early stage of vehicle development. For the study, we have used ADAMS/Car for modeling front and rear suspension system including steering system, and then used ADAMSlInsight for a design of experiment(DOE) study. To show the validity of simulation model. the simulation results of the base model were compared with the test results. Based on the validated model, we have performed a DOE study of suspension system static design factors(SDF) for enhancing ride & handling performance of an initial development vehicle. To examine the dynamic response of the vehicle with the proposed suspension, we have performed some handling simulations after building a full vehicle simulation model including PT, brakes, tires, sprung body by using data of base mother model.
Lee, Taeyul,Chung, Chulhoon,Chang, Yongjoon,Kim, Jaehyun Korean Society of Plastic and Reconstructive Surge 2015 Archives of Plastic Surgery Vol.42 No.5
Background The purpose of this study was to compare postoperative morbidities and functional outcomes of pectoralis major myocutaneous (PMMC) flap and cutaneous free flap reconstruction approaches in hypopharyngeal squamous cell carcinoma patients. Methods We retrospectively reviewed records from 99 patients who underwent hypopharyngeal reconstruction with a cutaneous free flap (n=85) or PMMC flap (n=14) between 1995 and 2013. Morbidity was classified into hospitalization, medical, or flap-related complications. Functional outcomes were classified into oral re-alimentation and decannulation time. Results The overall flap-related complication rate was higher in the PMMC flap group (n=8, 57.1%; P=0.019), but the medical morbidity rate was higher in the cutaneous free flap group (n=68, 80%; P=0.006). The rate of pneumonia was higher in the cutaneous free flap group (n=48, 56.5%; P=0.020). Pulmonary premorbidity was the variable most significantly associated with pneumonia (odds ratio=3.012, P=0.012). There was no statistically significant difference in oral re-alimentation and decannulation time between the two groups. Conclusions Although the functional superiority of free flaps has been reported in many studies, our results do not support this hypothesis. One limitation of our study is the relatively smaller flap size and fewer PMMC flap cases compared with the cutaneous free flap group. The low postoperative medical morbidity incidence rate in the PMMC flap group was clinically significant; however, the free flap group had more flap-related complications. Thus, PMMC flaps should be considered a viable option, especially for patients with pulmonary premorbidities.