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입자미세화가 Al-4.8%Cu-0.6%Mn 합금의 유동도에 미치는 영향
권영동(Young Dong Kwon),이진형(Zin Hyoung Lee),김경현(Kyoung Hyun Kim) 한국주조공학회 2002 한국주조공학회지 Vol.22 No.3
N/A A good fluidity of high strength Al-alloys is required to cast thin wall castings needed to reduce the weight of cast parts. The fluidity, measured as the length to which the metal flows in a standard channel, is affected by many factors, such as the pouring temperature, solidification type of the alloy, the channel thickness, melt head, mold materials and temperature, coating etc. Therefore the experimentally measured fluidity scatters very much and makes it difficult to estimate the fluidity of a melt with a few measurements. The effect of Ti content and grain refinement on the fluidity of high strength aluminum alloy was investigated with a test casting with 8 thin flow channels to reduce the scattering of the fluidity results. The fluidity of Al-4.8%Cu-0.6%Mn Al-6.2%Zn-l.6%Mg-l.0%Cu and well-known commercial aluminum alloy, A356 was tested. Initial content of Ti was varied from 0 to 0.2wt% and Al-5Ti-B master alloy was added for grain refinement. The flow length varied linearly with superheat. By adding Ti and Al-5Ti-B, the fluidity increased. The grain size decreased by adding grain refiner at the same time. The fluidity depended on the degree of grain refinement. The fluidity of the alloy solidifying in mushy type is improved by grain refinement, because grain refinement increases the solid fraction at the time of flow stoppage.
엣지 부각성 라플라시안 필터 기반 지능형 자율주행 물체인식 및 제어시스템 설계 및 구현
권영동(Young-Dong Kwon),강문식(Moon-Sik Kang) 대한전자공학회 2020 전자공학회논문지 Vol.57 No.3
본 논문에서는 자율주행을 위한 효율적인 물체인식 및 최적제어 기법을 제안한다. 제안된 시스템은 라인스캔 카메라를 사용하여 트랙 차선 중심을 정확하게 인식하도록 설계되었으며, LoG Filter를 활용하여 필터링 기능을 구현하였다. 실제 차량에서 많이 사용되고 있는 Infineon사의 TC275 모델에서의 MCU Board를 사용하여 자율주행 모형차 시스템을 제작하였다. 구현된 시스템은 카메라 센서를 통해 차선의 중심을 인지하여 차량을 정확한 위치를 찾도록 조향 조절이 가능하고, 나아가 규정 속도를 유지해주는 PID제어가 가능하다. 제안된 기법의 성능을 평가하기 위해서 속도 제한구역과 장애물 출현 등으로 인한 특수상황을 고려하여 실험을 수행하였다. 실험 결과를 분석하여, 제안된 시스템이 우수한 성능을 보임을 입증하였다. In this paper, we propose an efficient object recognition and optimal control scheme for autonomous driving. The proposed scheme uses the line scan camera to accurately recognize the center of the lane of the track, and the filtering operation is implemented using LoG Filter. An autonomous model car system was fabricated using the MCU board of Infineon"s TC275 model, which is widely used in actual vehicles. The implemented system can adjust the steering to find the exact position of the vehicle by recognizing the center of the lane through the camera sensor, and furthermore, PID control to maintain the specified speed is possible. In order to evaluate the performance of the proposed method, the experiment was performed considering the special situation due to the speed limit zone and obstacles. By analyzing the experimental results, we proved that the proposed system shows good performance
7075 및 7050 알루미늄 합금의 응고 거동 및 편석에 미치는 냉각 속도의 영향
최정윤(Jeong Yun Choi),권영동(Young Dong Kwon),이주원(Joo Won Lee),이진형(Zin Hyoung Lee) 한국주조공학회 2001 한국주조공학회지 Vol.21 No.6
N/A The effect of cooling rate on the solidification microstructure and segregation behavior of 7075 and 7050 aluminum alloy was investigated. Samples were solidified with cooling rates from 0.3 to 17°K/sec. Using the cooling curves of each sample, liquidus, eutectic and intermetallic reaction temperatures were estimated. The microstructures were characterized in terms of dendrite arm spacing and eutectic volume fraction. The segregation behavior of each alloying element of these alloys in various cooling rates was discussed.