• 한국철도학회:학술대회논문집
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• 한국철도학회 2009년도 춘계학술대회 논문집
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• pp.905-911
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• 2009

The viscosity drive method by the wheel which is widely used in the conventional railway systems needs a large friction force between the wheel and the guide-rail, which brings on a thrust force for a quick acceleration and a high-speed travelling. In addition, the viscosity drive method needs an increase of the vehicle weight for a large friction force. However, a maglev train is possible to be driven by the electro-magnet instead of the wheel, which produces a levitation and thrust force without any contact. In general, low-speed maglev train uses a linear induction motor(LIM) for propulsion that is operated under 300[km/h] due to the power-collecting and end-effect problems of LIM. In case of high-speed maglev train, a linear synchronous motor(LSM) is more suitable than LIM because of a high-efficiency and high-output properties. LSM has a driving principle as same as a conventional rotary synchronous motor(RSM), and the torque of RSM becomes the thrust force of LSM. A conventional LSM has relatively large air-gap compared with a conventional RSM. So, it must be achieved a design that is considered normal force by finite-asymmetric structure, end-effect on the entry and exit part, and support structure of a moving part. Therefore, in this research, authors accomplish a conceptualizing and basic design of a small-scaled LSM, and characteristics analysis using FEM.

• 동력기계공학회지
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• 제20권5호
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• pp.60-65
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• 2016

Dynamic performance of transmission has a substantial effect on dynamic performance and fuel efficiency of a vehicles. Dynamic performance of transmission and mass moments of inertia of transmission gears are related directly each other. Then a smaller amount of kinetic energy from vehicles that repeat acceleration and deceleration requires lighter rotating part in transmission. It is going to increases fuel efficiency as a result. In this study, equivalent inertia moments of inertia at different speeds were calculated by simplifying the transmission system. To find out lightening effect at low speed level gear on fuel efficiency, the powerflow of transmission was analyzed. And the lightning effect of the rotating parts in transmission is compared with the mass reduction of sprung parts in vehicle.

• 한국추진공학회:학술대회논문집
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• 한국추진공학회 2010년도 제35회 추계학술대회논문집
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• pp.807-808
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• 2010

비추력이 300초 정도 되는 발사체로 고도 200km 이상의 궤도에 페이로드를 진입시키기 위해서는 2단 이상의 단 구성이 필요하다. 전이궤도인 고도 200~250km 까지는 1단과 2단 로켓 엔진의 작동 영역이고 그 이상은 최상단 가속블록과 인공위성의 추진기관이 작동하는 영역이다. 최상단의 엔진은 페이로드를 목표한 궤도에 정확하게 투입시키기 위해 높은 추력은 아니지만 정밀한 제어를 필요로 한다. 현재 운용 중인 상단 엔진에 대한 조사와 정리를 통하여 개발 동향을 파악하고 향후 우리의 고성능 상단 엔진을 개발하는데 참고하고자 한다.

• 대한기계학회논문집A
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• 제28권11호
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• pp.1672-1684
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• 2004

In this paper, an active vibration control with the use of an air-cell seat for passenger cars is investigated. The roles of the air-cell inserted between the polyurethane foam of the seat and seat cover are first to extend the seat's capability to adopt various shapes of human body and to improve the ride-comfort against road disturbances. The air-cell seat is modeled as a 1-d.o.f. spring-damper system. Because an exact modeling of the air-cell itself is alomost impossible, its dynamic characteristics are analyzed through experiments. A road-adaptive gain-scheduled sky-hook control for the air-cell seat system is proposed. The skyhook gains are scheduled in such a way that the acceleration level transmitted to human body on various road conditions is minimized. Simulations and experimental results are provided.

• 대한인간공학회지
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• 제32권4호
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• pp.381-387
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• 2013

Objective: This paper studies the method of measuring whole-body vibration in the car and terms associated. Background: Human exposure to vibration can be broadly classified as localized and whole-body vibration. The whole-body vibration affects the entire body of the exposed person. It is mainly transmitted through the seat surfaces, backrests, and through the floor to an individual sitting in the vehicle. It can affect the comfort, performance, and health of individuals. Method: Human responses to whole-body vibration can be evaluated by two main standards such as ISO 2631 and BS 6841. The vibration is measured at 8 axes - three translations at feet, 3 translations of hip and two translations of back proposed by Griffin. B&K's sensors used in this study are the 3-axes translational acceleration sensor to measure the translational accelerations at the hip, back and foot. Results: The parameters associated with the whole-body vibration in the car are frequency weightings, frequency weighted root-mean-square, vibration dose values, maximum transient vibration value, seat effective amplitude transmissibility, ride values and ride comfort. Conclusion: Studied the evaluating methods of vibration exposure and ride comfort. Application: Evaluation of whole-body vibration in the car.

• 한국철도학회논문집
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• 제14권2호
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• pp.137-142
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• 2011

바이모달트램(Bimodal tram)은 현행 교통체계를 해소하고자 도입되는 신형식 차량으로 버스와 지하철의 장점을 지니고 있는 시스템이다. 이러한 차량의 도입으로 인해 전용선로인 파이프트러스교가 건설 되어지는데 기존에 시공되지 않은 새로운 형식의 교량으로 이에 대한 동적응답 특성에 대한 분석이 필요하다. 본 연구에서는 바이모달트램의 전용선로인 파이프 트러스교에 대하여 교량 하부에 센서를 부착하여 차량의 주행실험을 실시하였다. 또한, 실험을 통하여 신형식 교량에 대한 변위 및 최대 수직 수평가속도를 계측하여 동적응답 특성을 분석하였다. 이러한 실험결과를 바탕으로 수치해석을 실시하여 증속주행에 대한 거동을 예측하였다.

• 한국자동차공학회논문집
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• 제13권6호
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• pp.113-119
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• 2005

The passenger car drivers want in general to feel good driveability, but they sometimes feel uncomfortable by shock and jerk phenomenon when they push or release acceleration pedal with clutch engaged. In this paper, the shock and jerk characteristics are studied on the vehicles of the throttle-by-wire system. With this system, the throttle is not directly controlled by drivers but via a microprocessor. So the control logic of the throttle is very important on tip-in and tip-out driveability. Experiments were carried out on two vehicles which show different control characteristics. The torque control logics were analyzed by measuring cylinder pressures. The results show that special torque control logic is needed at tip-in/out state for good driveability.

• 한국해양공학회:학술대회논문집
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• 한국해양공학회 2003년도 춘계학술대회 논문집
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• pp.94-98
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• 2003

최근 해양 자원 확보의 중요성이 증대됨에 따라 이들 자원의 탐사 및 해양 연구에 필요한 심해 잠수정의 개발이 국내에서 진행되고 있다. 이에 따라 본 연구에서는 ROV 진수 시 파랑 하중에 의해 발생하는 ROV 케이블의 장력 변화에 대한 정량적 평가를 수행하였다. ROV carrier는 국내에서 운용 중인 온누리호를 모델로 하였으며, 파도에 의해 발생하는 선체 운동 해석 결과를 토대로, 이들 운동에 의해 발생하는 케이블의 장력을 선체. A-frame 및 ROV의 물리적, 기하학적 특성을 고려한 연성 동력학 해석을 통해 구하였다. 해석은 유한 요소 해석을 기반으로 하는 조화 가진 해석을 수행하였고, 선체 운동은 선수파와 횡파에 대해 각각의 해석 결과를 도출하였다.

• 한국자동차공학회논문집
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• 제23권6호
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• pp.615-622
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• 2015

Recently Digital-TachoGraph(DTG) was mounted mandatorily in commercial vehicles(Taxi, Bus, etc.). DTG records accurate and detailed information of the running state of vehicles related to traffic accident, such as Time, Distance, Velocity, RPM, Brake ON/OFF, GPS, Azimuth, Acceleration. Thus those standardized data can play an important role in traffic accident investigation and reconstruction. To develope the accurate and objective method using the DTG data for the reconstruction of traffic accident, we had conducted several tests such as driving test, high speed circuit test, braking test, slalom test at Korea Automobile Testing & Research Institute(KATRI), and collision test at Korea Automobile insurance repair Research and Training center(KART) with the vehicle equipped with several DTG. Development of the program which enables the reading and analysis of the DTG data was followed. In the experiments, we have found velocity error, RPM error, brake signal error and azimuth error in several products, and also non-continuous event data. The cause of these errors was deduced to be related to the correction factor, the durability of electronic parts and the algorithm.

• 한국안전학회지
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• 제22권6호
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• pp.13-19
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• 2007

Diesel car's smoke measurement equipment and method were investigated based on the exhaust gas regulations. Reflection photo method and light extinction method for measuring smoke were compared under conditions of both no load mode and Lug-down 3 mode. Free acceleration mode at no load condition was used for regular inspection of diesel car, and Lug-down 3 mode was used for fine inspection of the diesel car. A correlation between no load mode and Lug-down 3 mode was investigated in this research. The smoke measured with reflection photo method was 1.5${\sim}$2 times higher than that of light extinction method The correlation coefficient between reflection photo method and light extinction method for measuring smoke was 0.83, which shows comparatively high correlation between the two methods for measuring smoke in diesel engines.