• 한국자동차공학회논문집
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• 제8권5호
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• pp.165-172
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• 2000

The VDC(Vehicle Dynamic Control) is a control system whose target is to improve stability of a vehicle under lateral motion. A lateral vehicle motion, especially on a slippery road, can lead to a hazardous situation, and the situation can even worsen by the driver`s inappropriate response. In this paper, two VDC systems, a fuzzy-based controller and an LQR-based controller have been developed. The controllers take as input the yaw rate and the sideslip angle of either body or rear wheel, and they yield the direct yaw moment signal by which the vehicle can gain stability during cornering. Simulations have been conducted to evaluate the performance of the control system. The results indicated that the controllers can successfully improve vehicle stability under potentially dangerous driving conditions.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2001년도 춘계학술대회논문집B
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• pp.565-570
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• 2001

Vehicle dynamics control (VDC) system requires more information on driving conditions compared with ABS and/or TCS. In order to develop the VDC system, tire slip angles, vehicle side-slip angle, and vehicle lateral velocity as well as road friction coefficient are needed. Since there are not any cheap and reliable sensors, recent researches on parameter estimation have given rise to a number of parameter estimation techniques. This paper presents new vehicle model to estimate vehicle's yaw rate. This model is improved from the conventional 2 degrees of freedom vehicle model, so-called bicycle model, taking nonlinear effects into account. These nonlinear effects are: (i) tyre nonlinearity; (ii) lateral load transfer during cornering; (iii) variable gear ratio with respect to vehicle velocity. Estimation results are validated with the experimental results.

• 대한기계학회논문집A
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• 제36권5호
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• pp.487-495
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• 2012

요 제어는 풍력 터빈의 전력 생산과 구조물의 기계적인 하중 발생에 밀접한 관계를 갖고 있다. 풍력 터빈으로 불어오는 바람의 방향과 나셀(nacelle)의 방향이 일치하지 않을 경우 발생하는 요 오차에 의하여, 풍력 터빈의 에너지 회수 효율이 감소하고, 블레이드(blade)에는 비대칭/불평형 하중이 증가하게 된다. 따라서, 요 오차를 감소시키기 위한 요 제어 시스템은 풍력 터빈의 중요한 서브 시스템 중에 하나이다. 그러나, 요 운동은 요 축 주위에 발생하는 여러 하중들에 의하여, 그 운동의 빠르기가 제약을 받게 된다. 본 논문에서는 기본적인 요 시스템의 원리에 대하여 간략히 살펴보고, 요 운동에 의하여 회전 날개에 발생된 기계적 하중이 어떻게 요 축 주위의 하중들로 전파되는 지, 또한 이러한 하중들의 특성은 무엇인 지에 대하여 살펴보았다.

• 한국전자통신학회논문지
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• 제14권1호
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• pp.265-274
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• 2019

본 논문은 저가형 AHRS(: Attitude Heading Reference System)센서를 이용하여 무인 운송체(Unmanned vehicle)의 자세를 무향 칼만 필터 (Unscented Kalman filter)통해 추정하는 방법을 제안한다. 측정된 가속도와 지구자기장 값을 이용하여 UKF의 보정 단계에서 사용될 자세를 계산한다. 롤 (roll)과 피치 (pitch)는 가속도로부터 구해지며 요 (yaw)는 지구 자기장을 이용하여 연산한다. 이때 사용되는 지구자기장 측정값은 강철 효과(hard-iron effect)와 연철 효과(soft-iron effect)에 의해 쉽게 왜곡되기 때문에 계산된 요의 불확실성이 롤이나 피치의 불확실성에 비하여 크다. 본 논문은 이러한 불확실성을 줄이기 위하여 측정된 지구자기장에 포함된 편차성분을 추정하고 보정하여 더 정밀한 요값을 구한다. 제안된 방법을 수조에서의 무인 운송체 항법 실험을 통하여 검증하였다. 실험결과, 자세 추정 성능이 개선되고 이에 따라 위치 추정 성능도 개선됨을 확인하였다.

• 풍력에너지저널
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• 제13권4호
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• pp.17-25
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• 2022

In this study, the response characteristics of two semi-submersible platforms with an IEA 15 MW reference wind turbine are compared. The nacelle acceleration, platform motion and generator power of FOWT applying a VolturnUS-S platform developed by the University of Maine and PentaSemi platform developed by the Korea Research Institute of Ships and Ocean Engineering are compared in operational conditions. Numerical simulations are performed based on the marine environmental conditions of the U.S east coast. In the FOWT to which the PentaSemi platform is applied, the nacelle acceleration and platform pitch angle are rather high, but the results of both platforms satisfied the design criteria at all operating wind speeds. The platform yaw angle of PentaSemi platform to which a yaw control catenary mooring system is applied is significantly smaller than the platform yaw angle of VolturnUS-S. Also, despite the relatively large nacelle acceleration and platform pitch angle, the generator power is higher on the PentaSemi platform. This means that the generator power dominates the control system rather than the nacelle and platform motion.

• International Journal of Aeronautical and Space Sciences
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• 제15권4호
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• pp.412-418
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• 2014

This paper describes the development of variable stability system (VSS) control laws for the KFA-i to simulate the dynamics of KFA-m aircraft. The KFA-i is a single engine, Class IV aircraft and was selected as an in-flight simulator (IFS) aircraft, whereas the KFA-m is a simulated aircraft that is based on the F-16 aircraft. A 6-DoF math model of KFA-i aircraft was developed, linearized, and separated into longitudinal and lateral motion for VSS control law synthesis. The KFA-i aircraft has five primary control surfaces: two flaperons, two all movable horizontal tails, and one rudder. Flaperons are used for load control, the horizontal tails are used for pitch and roll rate control, and the rudder is used for yaw rate control. The developed VSS control law can simulate four parameters of the KFA-m aircraft simultaneously, such as pitch, roll, yaw rates, and load. The simulation results show that KFA-i follows the responses of KFA-m with high accuracy.

• International Journal of Automotive Technology
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• 제7권7호
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• pp.777-784
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• 2006

The lateral dynamic behaviours of a track inspection vehicle with laterally guided system are studied for the safety and comfort. A 10-DOF dynamic model is proposed counting for lateral and yaw motions. The equations for motions of the vehicle running on curved tracks at a constant speed are presented. It is shown by simulation that lateral guiding forces applied to the guiding wheels on the inner side of the track increase in a larger scale in comparison with those on the outer side when the vehicle passes through curved tracks with cant, and the front guiding spring forces is larger than the rears. Lateral vibrations due to yaw motions of the vehicle take place when the vehicle runs through curved tracks. Finally, effect of the lateral guidance on the vehicle dynamics is also examined and advantages of such a guiding system are discussed in some details. An optimal guided control is applied to restrain the lateral and yaw motions. The comparisons between the active and passive guidance explain the effect of the active control approaches.

• 동력기계공학회지
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• 제10권4호
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• pp.56-64
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• 2006

This paper shows the development process of a straight-type five-hole pressure probe for measuring three-dimensional flow velocity components. The data reduction method using a bi-cubic curve-fitting program in a new calibration map was introduced in this study. This new calibration map can be applied up to the application angle, ${\pm}55^{\circ}$ of a probe. As a result, for the application angle of ${\pm}45^{\circ}$, an error for yaw and pitch angles appeared from $-1.76^{\circ}\;to\;1.83^{\circ}$ and from $-1.91^{\circ}\;to\;1.75^{\circ}$, respectively. Moreover, an error for a vector magnitude and a static pressure compared with a dynamic one showed from -7.83% to 4.87% and from -0.73 to 0.77, respectively. Even though this data reduction method showed unsatisfactory errors in a vector magnitude, it resulted in an easy and simple application method. Especially, when it was applied to an actual flow field including a swirling flow, a good result came out on the whole. However, in order to obtain a better result, it is thought that a more sophisticated interpolation method needs to be introduced.

• 풍력에너지저널
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• 제15권1호
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• pp.43-49
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• 2024

This study performed a response analysis according to the transmission error of the yaw drive. To perform the response analysis, the excitation source of the transmission error was modeled and the outer ring of the first stage bearing and the outer ring of the output shaft bearing were used as measurement positions. The response results were analyzed based on the vibration tolerance values of AGMA 6000-B96. As a result of the response of the first stage bearing outer ring, the maximum displacement of the first stage planetary gear system was 5.59 and the maximum displacement of the second to fourth stage planetary gear systems was 4.21 ㎛ , 3.13 ㎛ , and 25.6 ㎛ . In the case of the output shaft bearing outer ring, the maximum displacement of the first stage planetary gear system was 1.73 ㎛, and the maximum displacement of the second to fourth stage planetary gear system was 1.94 ㎛, 0.73 ㎛, and 2.03 ㎛. According to AGMA 6000-B96, the vibration tolerance of first stage is 17.5 ㎛, and the vibration tolerance of the second to fourth stages is 58 ㎛, 80 ㎛, and 375 ㎛, which shows that the vibration tolerance is satisfied and it is safe.

• 한국기계가공학회지
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• 제17권6호
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• pp.31-37
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• 2018

In order to improve stability and controllability of SUV vehicle, Integrated Dynamics Control system with Steering system (IDCS) was developed. Eight degree of freedom vehicle model and front and rear steering system model were used to design IDCS system. It also employs Fuzzy logic control method to design integrate control system. The performance of IDCS was evaluated with two road conditions and several driving conditions. The result shows that SUV vehicle with IDCS tracked the reference yaw rate under all tested conditions. IDCS reduced the body slip angle also. It represents IDCS improves vehicle stability and steerability.