• 한국자동차공학회논문집
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• 제20권6호
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• pp.146-155
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• 2012

This study aims to analyze durability by comparing displacement on vibration at driving bicycle frame models of 1, 2, 3 and 4. Among maximum equivalent stresses at 4 kinds of models, model 1 has highest value with 410.39 MPa and becomes 30 times than model 4 with lowest value. The natural frequency number at Model 4 increases more than the other models. Among four models, the number of frequency at model 1 becomes lowest at harmonic vibration with real loading condition. In cases of four kinds of models, the maximum stress is shown near the assembly of rear wheel and the maximum displacement is shown near saddle assembly at this harmonic condition. The structural result about this study can be effectively utilized on the design of bicycle frame by investigating durability and prevention against its damage.

• 산업융합연구
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• 제17권4호
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• pp.125-129
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• 2019

자전거를 이용하는 사람들의 수가 증가함에 따라 자전거 사고의 수도 증가하고 있습니다. LED 조명을 사용하면 자전거를 탈 때 자전거 사고를 최대 11 % ~ 44 %까지 줄일 수 있습니다. 자전거의 헤드라이트는 자전거 라이더의 반대쪽에 노출 효과를, 미등은 후면 자전거 라이더에 노출 효과를 제공하여 안전성을 향상시킵니다. 본 연구에서는 제어 버튼 신호에 응답하여 LED에 의한 방향 전환을 표시 할 수 있는 자전거 안전장치를 구현 하였다. 이 신호는 고정 된 시간 동안 자전거의 페달과 휠에 장착 된 LED 조명을 모듈 유형의 발광 또는 깜박임으로 만듭니다. 야간에 자전거를 타는 사람이 자전거를 타는 경우 LED를 사용하여 안전을 향상시킬 수 있는 페달의 자전거 보조 장치가 본 연구에서 개발되었습니다. 무선 통신 기술을 적용한 자전거 안전장치는 미래에 에너지, 환경 및 안전과 같은 사회적 문제를 해결하기 위한 대체 기술이 될 것으로 예상됩니다.

• 한국기계가공학회지
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• 제11권3호
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• pp.122-129
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• 2012

This study investigates structural and vibration analyses according to the thickness of bicycle frame tube. The model of bicycle frame has the dimension as length of 862mm, width of 100mm and hight of 402.5mm. There are 3 kinds of models with tubes of top, down and seat at bicycle frame as thicknesses of 10, 15 and 20mm. The maximum displacement and stress occur at the center part of seat stay and at the installation part of rear wheel respectively. Maximum displacements become 0.031936, 0.029159 and 0.027984mm in cases of thicknesses of 10, 15 and 20mm respectively. In case of thickness of 20mm among 3 cases, maximum displacement becomes lowest. But maximum stresses become 10.019, 8.5492 and 9.2511MPa in cases of thicknesses of 10, 15 and 20mm respectively. In case of thickness of 15mm among 3 cases, maximum stress becomes lowest. There is no resonance at practical driving conditions and natural frequency remains almost unchanged along the change of thickness. In case of the displacement due to vibration mode, the displacement difference at thickness between 15mm and 20mm becomes 1/2 times than that between 10mm and 15mm. Design at bicycle frame tube becomes most economical and durable effectively in case of thickness of 15mm among 3 cases.

• 한국융합학회논문지
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• 제4권1호
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• pp.1-7
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• 2013

본 연구는 자전거 안전 시스템 장치 개발에 관한 연구과제로 대상기술의 개요, 기술개발의 필요성 및 성공 시 파급효과, 기술개발의 목표, 개발방법, 기술개발 성공 시 판매 수출 등 사업화 방법, 시작품 성능 및 제원(speculation)에 대해 다음과 같은 연구 계획을 가지고 추진하였다. 대상기술(제품)의 개요는 이동시 안전운행을 위한 장치의 개발 및 고가의 자전거를 위한 보관 시 안전장치 개발에 있다. 기술개발의 필요성(기존의 애로사항 등) 및 성공 시 파급효과로는 자전거 보급 확대에 따른 이동량 증가에 따라 각종 안전사고 발생을 줄일 필요가 대두되었고, 욕구의 다양화로 고가의 자전거 보급이 늘어남에 따라 도난, 분실 등의 사고가 우려되어 개발하게 되었고, 안전사고를 미연에 방지하므로 부상치료, 재산손실에 대한 경제적 손실 억제하는 효과를 가지고 있다. 기술개발의 목표는 자전거 운행시 안전한 방향전환을 위한 시그널장치, LED 헤드라이트와 도난을 대비한 도난방지 시스템을 사용자가 별도의 도움 없이 혼자서 손쉽게 장착할 수 있는 장치를 개발하는데 있다.

• International Journal of Automotive Technology
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• 제5권2호
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• pp.69-76
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• 2004

This paper evaluates the effectiveness of four-wheel-steering system from the viewpoint of lane-keeping control theory. In this paper, the lane-keeping control system is designed on the basis of the four-wheel-steering automobiles whose desired steering response is realized with the application of model matching control. Two types of desired steering responses are presented in this paper. One is zero-sideslip response, the other one is steering response which realizes zero-phase-delay of lateral acceleration. Using simplified linear two degree-of-freedom bicycle model, simulation study and theoretical analysis are conducted to evaluate the lane-keeping control performance of active four-wheel-steering automobiles which have different desired steering responses. Finally, the evaluation is conducted on straight and curved roadway tracking maneuvers.

• 오토저널
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• 제12권3호
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• pp.21-29
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• 1990

Equipments of passenger cars with modern technologies are gaining their importance. Related with such developments, the four-wheel steering system (4WS) was introduced recently to a few passenger cars in the market. The most important research goal on this new steering system is improvement of active safety, in other words, improvement of handling characteristics of vehicle stability and maneuverability. This paper presents a computer-based study about the effects of 4WS system on the vehicle handling characteristics. A simple bicycle model of 2 d.o.f. is used for the development of four wheel control algorithms of 4WS system, and the rear wheel control strategies are applied to a complex vehicle model of 16 d.o.f. for simulation of selected ISO-driving tests. The 4WS systems, which reduce the sideslip angle at the mass center of vehicle to almost zero, show much improved handling characteristics compared to that of the conventional 2WS system. These 4WS systems, however, result in vehicles with eigen-steer characteristics of extreme understeer behaviour.

• 한국자동차공학회논문집
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• 제3권3호
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• pp.66-78
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• 1995

In this paper, we address vehicle modeling and dynamic analysis of four wheel steering systems (4WS). 4WS is one of the devices used for the improvement of vehicle maneuverability and stability. All research done here is based on a production vehicle from a manufacturer. To study actual system response, a three dimensional, full vehicle model was created. In past research of this type, simple, two dimensional, bicycle vehicle models were typically used. First, we modelled and performed a dynamic analysis on a conventional two wheel steering(2WS) vehicle. The modeling and analysis for this model and subsequent 4WS vehicles were performed using ADAMS(Automatic Dynamic Analysis of Mechanical Systems) software. After the original vehicle model was verified with actual experiment results, the rear steering mechanism for the 4WS vehicle was modelled and the rear suspension was changed to McPherson-type forming a four wheel independent suspension system. Three different 4WS systems were analyzed. The first system applied a mechanical linkage between the front and rear steering mechanisms. The second and third systems used, simple control logic based on the speed and yaw rate of the vehicle. 4WS vehicle proved dynamic results through double lane change test.

• 한국자동차공학회논문집
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• 제2권5호
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• pp.101-109
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• 1994

Recently, four-wheel steering systems have been developed and studied as one of the latest automotive technologies for improving the handling characteristics of a vehicle. In much of the proposed four-wheel steering systems, the side slip angle at the vehicle's center of gravity is maintained at zero. This approach allows the greater maneuverability at low speed by means of counter-phase rear steering and the improved stability at high speed through same-phase rear steering. In this paper, the effects of several four-wheel steering systems are studied and discussed on the responsiveness and stability of the vehicle by using the linear analysis. Especially, the effects of the cornering stiffnesses of both front and rear wheels are investigated on the yaw velocity gain and critical speed of the vehicle.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 2001년도 ICCAS
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• pp.173.3-173
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• 2001

In this paper, attitude control of autonomous system using bike based on variable structure control is discussed. Variable structure control is more than a promising technique in the field of nonlinear control. It permits the realization of very robust and simple regulators, with appealing sliding mode characteristics especially if the considered dynamics requires a very short sampling time. We derive dynamic equation of it and demonstrate that the designed controller stabilizes attitude simultaneously regardless of wheel position by computer simulation.

• 전력전자학회:학술대회논문집
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• 전력전자학회 2010년도 하계학술대회 논문집
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• pp.63-64
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• 2010

본 논문에서는 전기자전거용 BLDC를 구동할 수 있는 구동제어시스템을 설계하였으며, BLDC 전동기와 구동원리에 대해 특성을 파악하였다. 제어보드는 TI사의 TMS320F2808을 이용하여 6-스텝 인버터를 구동하였으며, PI제어를 적용하여 전류제어를 통해 전기자전거용 BLDC 구동장치를 구현 하였다.