• 한국항공우주학회지
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• 제32권4호
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• pp.34-42
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• 2004

본 논문에서 위성의 롤/요 자세제어를 위해 더블 김벌을 이용하며 2 종류의 피드백 제어기를 설계하였다. 하나는 롤과 요 제어압력에 위상 차이가 없는 PD 제어기이고 다른 하나는 요 제어입력에 위상지연이 있는 PD 제어기이다. 위상지연 보상기는 요각 제어를 위한 1차 시스템으로 설계하였다. 일정한 외란과 초기 뉴테이션 오차가 있는 경우에 대해 시뮬레이션하여 요각의 정상상태 오차와 rising time 의 결과로부터 위상지연 보상기가 효과적임을 검증하였다. 본 시뮬레이션에 사용된 변수 값은 무궁화위성 1호를 대상으로 하였다.

• Structural Engineering and Mechanics
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• 제56권6호
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• pp.1021-1040
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• 2015

An effective method to calculate aerodynamic loads and aeroelastic responses of large wind turbine tower-blade coupled structures in yaw condition is proposed. By a case study on a 5 MW large wind turbine, the finite element model of the wind turbine tower-blade coupled structure is established to obtain the modal information. The harmonic superposition method and modified blade-element momentum theory are used to calculate aerodynamic loads in yaw condition, in which the wind shear, tower shadow, tower-blade modal and aerodynamic interactions, and rotational effects are fully taken into account. The mode superposition method is used to calculate kinetic equation of wind turbine tower-blade coupled structure in time domain. The induced velocity and dynamic loads are updated through iterative loop, and the aeroelastic responses of large wind turbine tower-blade coupled system are then obtained. For completeness, the yaw effect and aeroelastic effect on aerodynamic loads and wind-induced responses are discussed in detail based on the calculating results.

• 기계와재료
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• 제23권3호
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• pp.182-189
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• 2011

전 세계적으로 대체에너지 개발이 활발해지면서 국내에서도 풍력발전에 대한 관심이 높아지고 있다. 풍력발전을 신재생에너지 중에서 가장 상업화에 앞서 있으며 급속한 시장 확대와 산업의 발전을 가져온 분야이다. 1990년대에 개발되어 설치 운용되고 있는 약 20만대의 0.5 MW ~ 3 MW급 중대형 풍력발전기가 세계 여러 곳에서 상업발전을 하고 있으며, 국내에서는 제주도 행원풍력발전단지에 1998년부터 2003년 4월까지 총 15기(약 203억 원 투입)의 풍력 발전기가 도입되어 세워져 있으며, 1998년 8월에 600kW 풍력발전기 1 2호기의 상업운전을 최초로 시작하였다. 최근 풍력발전기의 설치 환경이 육상에서 해상으로 변하면서 5MW급 초대형 풍력발전기의 상용화가 시도되고 있으며 수요 또한 급증하고 있다. 본고에서는 전량 수입에 의존하고 있는 풍력발전기의 핵심 부품인 Yaw system(yaw bearing & drive)의 국내외 시장 동향과 초대형 요 베어링 및 고 강성 유성기어 감속기의 특성을 분석하였으며, 특히 전략적 국산화 개발필요성을 강조하였다.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 2004년도 ICCAS
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• pp.2055-2058
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• 2004

This paper formulates a yaw angle determination algorithm for earth-point satellite. The algorithm based on vector observation, is implemented with the limited vector measurements. The proposed algorithm doesn't require gyro measurement data but magnetic sensor measurement data. In order to confirm the usefulness of the proposed method, we investigate the simulated telemetry data of the KOMPSAT-2, a satellite that is scheduled to be launched into a 685km altitude sun synchronous circular orbit in 2005.

• 한국정밀공학회지
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• 제19권11호
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• pp.65-74
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• 2002

This paper examines the usefulness of a Brake Steer System (BSS), which uses differential brake forces for steering intervention in the context of Intelligent Transportation Systems (ITS). In order to help the car to turn, a yaw moment can be achieved by altering the left/right and front/rear brake distribution. This resulting yaw moment on the vehicle affects lateral position thereby providing a limited steering function. The steering function achieved through BSS can then be used to control lateral position in an unintended road departure system. A 8-DOF nonlinear vehicle model including STI tire model will be validated using the equations of motion of the vehicle. Then a controller will be developed. This controller, which will be a PID controller tuned by Ziegler-Nichols, will be designed to explore BSS feasibility by modifying the brake distribution through the control of the yaw rate of the vehicle.

• 한국자기학회지
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• 제4권2호
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• pp.106-113
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• 1994

초전도 반발식 자기부상열차의 동특성을 해석하기 위하여 외력에 의하여 대차가 기울어진 경우에 차량에 가해지는 전자력을 계산하였다. 집중부하방식의 열차에 있어서 크게 나타나는 단부효과 를 고려하기 위하여 공극자속의 형태에 대한 가정없이 자속분포를 계산하였으며, 대차의 옆질(roll), 뒷질(pitch) 및 편주(yaw)시의 전자력특성과 복원토오크를 검토하였다. 6개의 초전도자석이 탑재된 대 차가 차량의 양쪽에 설치된 열차에 대해서 계산한 결과, 토오크의 방향은 차량을 안정하게 하는 방향 으로 나타나서 본 자기부상시스템은 기본적으로 안정한 시스템임을 보여주고 있다.

• 동력기계공학회지
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• 제12권4호
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• pp.18-25
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• 2008

This paper investigated the new calibration algorithm of a straight-type five-hole pressure probe necessary for calculating three-dimensional flow velocity components. The new data reduction method Includes a look-up, a geometry transformation such as the translation and reflection of nodes, and a binary search algorithm. This new calibration map was applied up to the application angle, ${\pm}55^{\circ}$ of a probe. As a result, this data reduction method showed a perfect performance without any kind of interpolation errors In calculating yaw and pitch angle from the calibration map.

• 한국자동차공학회논문집
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• 제7권5호
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• pp.240-248
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• 1999

This paper presents a lane-change collision avoidance control algorithm for autonomous vehicles that will be used in AHS(Automated Highway System). In the proposed control algorithm, nominal control inputs are generated by solving the inverse vehicle dynamic equations of motion for a lane-change maneuver. In addition, a corrective steering input from preview as well as DYC (Direct Yaw Moment Control) may be included to reduce unpredictable errors and to insure yaw directional stability, respectively. The performance of the algorithm is evaluated with an ABS HILS system which consist of 17 DOF vehicle model and real ABS hardware parts. The HILS simulation results show that the proposed algorithm may be used for emergency lane-change maneuvers for autonomous vehicles.

• 한국자동차공학회논문집
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• 제5권3호
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• pp.209-219
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• 1997

A fuzzy driver model based on a preview-predictor and yaw rate is developed. The model is used to investigate the handling performance of two wheel steering system(2WS) and four wheel steering system(4WS) vehicles. The two degree-of- freedom model which has yaw and lateral motion predicts the path of the vehicles. Based upon the yaw rate and lateral deviations, the fuzzy engine describes the human driver's complicated control behavior which is adjusted for the driving environment. Both typical single lane change maneuver and double lane change maneuver are adopted to demonstrate the feasibility of fuzzy driver model.

• 한국자동차공학회논문집
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• 제20권2호
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• pp.15-20
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• 2012

This study is to propose and develop an integrated dynamics control system to improve and enhance the lateral stability and handling performance. To achieve this target, we integrate an AFS and a 4WS systems with a fuzzy logic controller. The IDCS determines active additional steering angle of front wheel and controls the steering angle of rear wheel. The results show that the IDCS improves the lateral stability and controllability on dry asphalt and snow paved road when double lane change and step steering inputs are applied. Yaw rate of the IDCS vehicle tracks reference yaw rate very well and body slip angle is reduced about by 50%. Response time of the IDCS vehicle is also decreased.