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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.
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>
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.
차량 쏠림 민감도 분석을 이용한 쏠림 개선에 관한 연구
노승진(Seungjin Noh),한성제(Sungje Han),황준효(Junhwyo Hwang),김상진(Sangjin Kim),이철훈(Chulhoon Lee),김우신(Woosin Kim),신상하(Sangha Shin),최진호(Jinjo Choi),장진희(Jinhee Jang),김인동(Indong Kim) 한국자동차공학회 2009 한국자동차공학회 부문종합 학술대회 Vol.2009 No.4
Vehicle pull is one of the most important problem on the vehicle quality from customers. To understand the vehicle pull, this paper describes vehicle pull phenomenon by considering causing factors of conicity and PRAT, vehicle factors of wheel alignment, and the external environment factor of road slope and weight. Those factors must be analyzed to improve the vehicle pull tendency. Therefore, by using Pull sensitivity analysis, vehicle pull simulation which makes it possible to consider the effect of passenger and road slope, PRAT, conicity and wheel alignment, is applied to evaluate and Steering Wheel Torque.
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.
Design of eMMC Controller with Virtual Channels for Multiple Processors
Chanho Lee,Chulhoon Kim 대한전자공학회 2018 Journal of semiconductor technology and science Vol.18 No.2
Portable embedded systems includes several non-volatile memory devices for the external storage. Multiple processors and multiple processing are popular and reading and writing data in the storage limit the performance of the system. The conventional architectures combine the devices to a single channel or assign the devices to multiple channels one by one to increase the performance. However, performance improvement depends on the applications due to the various requirements of data transfer. In this paper, we propose architecture for non-volatile memory controller with virtual channels for systems with multiple processors. The proposed architecture has an AMBA AXI master interface for data transfer and an AMBA APB slave interface for writing instructors and reading status and responses to be connected to a host system. Device adapters are connected to the devices and form physical channels. It can respond to the requests of the multiple processors by configuring virtual channels which have a single or multiple physical channels and can be activated independently. The waiting times and the transfer times of memory requests can be traded-off dynamically for the better system performance. An eMMC controller is designed using Verilog-HDL according to the proposed architecture, and is implemented using an FPGA. The operation of the controller is verified by simulation and measurement.