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성형기계용 하이드로포밍 제어기 개발을 위한 유압시스템 모델링
문철우(Chulwoo Moon),이동원(Dong-Won Lee),송세일(Se-Il Song) 한국자동차공학회 2009 한국자동차공학회 학술대회 및 전시회 Vol.2009 No.11
Hydroforming application has been increased in interests in reducing weight of autombile for a vehicle design. Main issues are how the intensifier actuator and axial feeding actuators are controled for the hydroforming application. In this study, hydraulic system including intensifier and axial feeding actuators has been modeled for the development of hydroforming control system. The sevo-valve actuator system is modeled as a linearized equation for nonlinear flowrate charcteristic. The material to be hydroformed is modeled as a simple spring-damed system. The suggested hydraulic system is simulated with a control scenario for hydroforming mechanism in Matlab/Simulink environment. In the results, each axial feeding actuator follows well the referred position. Otherwise, limitation exists in force control for intensifier actuator because of the linearized material model.
정재승(Jeong JaeSeung),문철우(Moon ChulWoo),김상균(Kim Sang-Kyun) 한국인사관리학회 2016 조직과 인사관리연구 Vol.40 No.1
본 연구는 사외이사의 독립성이 기업 전략변화에 미치는 영향과 이들 두 변수 간의 관계에 있어서 과거 경영성과의 조절효과에 대해 분석하였다. 2006년부터 2008년까지 3개년의 시계열을 갖는 142개 국내 상장기업의 패널자료를 이용한 실증분석 결과, 사외이사의 독립성과 기업의 전략 변화 간에 통계적으로 유의미한 관계는 확인되지 않았다. 그러나 과거 경영성과는 이들 두 변수간의 관계에서 유의미한 조절효과를 가지고 있음을 확인하였다. 특히 과거 경영성과가 낮을수록 사외이사의 독립성과 전략변화 간의 정(+)의 관계를 확인하였다. 즉 경영성과가 낮은 상황에서 사외이사의 독립성이 전략변화에 정(+)의 영향을 미치는 것을 확인하였다. 본 연구결과는 글로벌 금융위기 이후 기업지배구조 개선에 대한 관심이 재차 높아지고 있고 경영환경 변화 및 기업 간 무한경쟁으로 인해 기업의 전략적 변화의 중요성이 증가하고 있는 시점에서 기업지배구조 메커니즘으로서 핵심적 역할을 담당하는 사외이사의 독립성이 기업의 전략 변화에 미치는 영향에 관해 실증하여 유의미한 결과를 도출하였다는 점에서 향후 바람직한 기업 지배구조 체제를 확립하고자 하는 기업의 경영실무나 유관기관의 정책업무에 유익한 참고자료가 될 수 있을 것으로 기대한다. The world economy experienced a global crisis in 2008. After this crisis, corporate governance have generated considerable attention in both the business and academic community. Outside directors are believed to be more effective means than other in corporate governance. Most of researches about outside directors have analyzed the relationship between outside directors and corporate performance from the prospective of outside directors’s control role. Outside directors are recognized as having the potential to influence strategic changes in corporate. However, there is considerable debate regarding the strategic role of outside directors. This paper examined the relationship between outside directors and corporate strategic changes from the prospective of service role. Using a random sample of 132 Korean firms over the 2006-2008. Our finding will draw attention to the need for the strategic role of outside directors.
딥러닝을 활용한 전기자동차 감속기 베어링의 고장 특징 추출
정기철(Kicheol Jeong),문철우(Chulwoo Moon),진효민(Hyomin Jin) 한국자동차공학회 2022 한국자동차공학회 부문종합 학술대회 Vol.2022 No.6
Recently, an EV (electric vehicle) is the key word of world-wide vehicle industry. The EV is actuated by a traction motor. In order to adjust a torque of the traction motor, a gearbox is necessary part of the EV. The gearbox consists of gears, bearings, and shafts. Especially, the input shaft bearings are subjected to several tons of axial load. Therefore, the fault caused by axial load in bearings has a negative impact on driving quality and vehicle safety. Consequently, the bearing fault diagnosis method is necessary especially EV power train system. In this paper, the gearbox fault feature extraction method is proposed. The proposed method constitutes a training part and an implementation part. In the training part, two accelerometers are used to implement adaptive noise cancellation algorithm. Using this preprocessed signal, supervised learning is conducted. In the implementation part, only one accelerometer is used. Consequently, the pre-trained deep learning architecture generates enhanced signal and fault features are extracted. In order to validate the proposed method, experiments using power-train dynamometer is conducted.
주행 한계상황 모사 기반의 디지털 클러스터 검증 기술 개발
함휘수(Hwisoo Ham),김주형(Joohyung Kim),문철우(Chulwoo Moon),황정현(Junghyun Hwang) 한국자동차공학회 2022 한국자동차공학회 부문종합 학술대회 Vol.2022 No.6
In recent, a digital cluster is recognized one of major part as a human vehicle interface for future vehicle. However, it is difficult to validate the digital cluster without vehicle integration and test because it operates based on communication signals from the other parts in a vehicle. In this study, a specific test system is proposed for a digital cluster in order to evaluate its malfunction prior to vehicle integration. The system includes a full vehicle model and driving environments, and it is wired to a digital cluster to communicate each other in real-time. The suggested test system is validated by comparing the vehicle dynamic simulation results and display results of the digital cluster based on predefined specific abnormal and critical driving situations.
일반인 대상의 필드 시험을 통한 제동시스템 부압 부족 시나리오 연구
이예쁜(Yeppeun Lee),이영석(Youngseok Lee),문철우(Chulwoo Moon),정창현(Changhyun Jeong) 한국자동차공학회 2018 한국자동차공학회 부문종합 학술대회 Vol.2018 No.6
A conventional braking system is equipped with a vacuum booster that utilizes the negative pressure of the engine as a power. The supply of engine negative pressure is not constant, and the charge rate depends on several factors. In particular, brake pedal is sometimes felt to be harder than usual due to traffic conditions or driver habits. This case is defined as the time when the negative pressure is insufficient and we have examined such cases. In order to investigate the case, the tester drove a test vehicle that records real-time vehicle information and negative pressure status, and made it run on a motorway, a mountain road, and a city road. This paper aims to propose an evaluation scenario for the response and coherence of the braking system through the case analysis.