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An Improvement Study on Brake System for KUH-1 (한국형 기동헬기의 제동장치 개선에 관한 연구)

  • Choi, Jae Hyung;Lim, Hyun-Gyu;Yoon, Jong Jin;Kang, Deuk Soo
    • Journal of the Korean Society for Aeronautical & Space Sciences
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    • v.45 no.4
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    • pp.292-299
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    • 2017
  • The KUH-1's Wheel Brake Assembly which is Brake System is an essential component to perform flight mission for pilot. It has function of taxing, differential braking and parking to sustain landing capability. However, the skid and abrasion of tire were occurred in mass-produce operation. Also, if it is occurred on the ground, the flight can not be performed. In this case, the defect is a major cause of the decrease in the operation rate of aircraft. In this paper, the cause of the defect in flight was identified and the failure process was organized. Also, it describes design improvements which was derived from troubleshooting and suggests verification results of flight test.

Vibration of Steel Composite Railway Bridges under High Speed Train (고속열차하중 하의 강합성형 철도교의 진동)

  • Chang, Sung Pil;Kwark, Jong Won;Ha, Sang Gil;Kim, Sung Il
    • Journal of Korean Society of Steel Construction
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    • v.10 no.4 s.37
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    • pp.577-587
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    • 1998
  • The influences of high speed train on the dynamic responses of steel composite railway bridges are investigated. The bridge system which has two I-girder and several cross beams is modeled with plate and frame elements. With assumption of concrete slabs are fully connected with steel girders, the offset between slabs and girders is modeled using constraint equation. The track system is modeled using beams on elastic foundation theory. And, the TGV train model is developed in 2-dimension considering bouncing and pitching motion. And braking action of vehicle is considered using speed dependent braking function. To investigate the behavior of bridges due to moving trains, parametric studies on the variation of natural frequency of bridge, speed parameter, vehicle modeling method, braking action of train, etc are performed.

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Integrated Chassis Control System with Fail Safety Using Optimum Yaw Moment Distribution (최적 요모멘트 분배 방법을 이용한 고장 안전 통합 섀시 제어기 설계)

  • Yim, Seongjin
    • Transactions of the Korean Society of Mechanical Engineers A
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    • v.38 no.3
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    • pp.315-321
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    • 2014
  • This paper presents an integrated chassis control system with fail safety using optimum yaw moment distribution for a vehicle with steer-by-wire and brake-by-wire devices. The proposed system has two-level structure: upper- and lower-level controllers. In the upper-level controller, the control yaw moment is computed with sliding mode control theory. In the lower-level controller, the control yaw moment is distributed into the tire forces of active front steering(AFS) and electronic stability control(ESC) with the weighted pseudo-inverse based control allocation(WPCA) method. By setting the variable weights in WPCA, it is possible to take the sensor/actuator failure into account. In this framework, it is necessary to optimize the variables weights in order to enhance the yaw moment distribution. For this purpose, simulation-based tuning is proposed. To show the effectiveness of the proposed method, simulations are conducted on a vehicle simulation package, CarSim.

Methodology for Estimating Safety Benefits of Advanced Driver Assistant Systems (첨단 운전자지원시스템의 교통안전 효과추정 방법론)

  • Jeong, Eunbi;Oh, Cheol
    • The Journal of The Korea Institute of Intelligent Transport Systems
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    • v.12 no.3
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    • pp.65-77
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    • 2013
  • Recent advanced sensors and communication technologies have been widely applied to advanced safety vehicle (ASV) for reducing traffic accident and injury severity. To apply the advanced safety vehicle technologies, it is important to quantify the safety benefits, which is a fundamental for justifying application. This study proposed a methodology for quantifying the effectiveness of the advanced driver assistant system (ADAS), and applied the methodology to lane departure warning system (LDWS) and automatic emergency braking system (AEBS) which are typical advanced driver assistant systems. When the proposed methodology is applied to 2008-2010 gyeonggi-province crash data, LDWS would reduce about 10~14% of relevant crashes such as head-on, run-off-the road, rollover and fixed-object collisions on the road. In addition, AEBS could potentially prevent about 50% of total rear-end crashes. The outcomes of this study support decision making for developing not only vehicular technology but also relevant safety policies.