• 자동차안전학회지
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• 제8권1호
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• pp.13-18
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• 2016

More than 80 percent of traffic accidents related with lane departure believed to be the result of crossing the lane due to either negligence or drowsiness of the driver. Lane-departure related accident in the highway usually involve high fatality. Even though LDWS is believed to prevent accident 25% and reduce fatalities by 15% respectively, its effectiveness in performance is yet to be confirmed in many aspects. In this study, the vehicle lateral locations relative to warning zone envelop (earliest and latest warning zone) defined in ISO standard, ECE and NHTSA regulations are compared with respect to various factors including delays, vehicle speed and vehicle heading angle with respect to the lane. Since LDWS is designed to be activated at the speed over 60 km/h, vehicle speed range for the study is set to be from 60 to 100 km/h. The vehicle heading angle (yaw angle) is set to be up to 5 degree away from the lane (abrupt lane change) considering standard for lane change test using double lane-change test specification. The TLC is calculated using factors like vehicle speed, yaw angle and reaction time. In addition, the effect of vehicle type and reaction time have been considered to assess LDWS safety.

• 한국군사과학기술학회지
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• 제8권4호
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• pp.5-13
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• 2005

The impact of a long-rod penetrator into oblique plates with combined obliquity and yaw is investigated. The study was done using a newly developed three dimensional dynamic and impact analysis code, which uses the explicit finite element method. Through the comparison of simulation result with experimental result and other code's result, the adaptability and accuracy of the developed code is evaluated under the complex situation in which yaw angle and oblique angle exist simultaneously. As a result of comparison, it has found that deformed shape, residual length and velocity, rotational velocity of long-rod show good agreement with experimental data. Through this study, the applicability and accuracy of the code as a metallic armour system design tool is verified.

• 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.

• 한국정밀공학회지
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• 제14권7호
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• pp.137-143
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• 1997

In this study, handling simulation of a passenger car is carried out to see the effects of suspension compliance, roll stabilizef bar and chassis flexibility. The front suspension of the car is a MacPherson strut type and the rear suspension is a multi-link type. The following five DADS models are constructed and compared to verify the effects of suspension compliance and chassis flexibility during lane change. (1) Vdhicle model without hard point compliance and stabilizer, (2) Vehicle model with hard point compoiance, (3) Vehicle model with hard point compliance and stabilizer, (4) Vehicle model with hard point compoiance, stabilizer, and one vibration mode of the chaxxis. (5) Vehicle model with hard point compliance, stabilizer, and three vibration modes of the chassis. The result shows that hard point compliance and stabilizer are significant in roll angle, and the flexibility of the chassis affects the yaw angle and yaw rate.

• 한국자동차공학회논문집
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• 제20권6호
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• pp.17-23
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• 2012

An integrated dynamic control (IDCF) with an active front steering system and an active rear braking system is proposed and developed in this study. A fuzzy logic controller is applied to calculate the desired additional steering angle and desired slip of the rear inner wheel. To validate IDCF system, an eight degree of freedom, nonlinear vehicle model and a sliding mode wheel slip controller are also designed. Various road conditions are used to test the performance. The results show that the yaw rate of IDCF vehicle followed the reference yaw rate and reduced the body slip angle, compared with uncontrolled vehicle. Thus, the IDCF vehicle had enhanced lateral stability and controllability.

• 대한기계학회논문집A
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• 제41권10호
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• pp.967-974
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• 2017

본 연구에서는 횡가속도 센서 계측 신호 기반의 기준 차량 요레이트 모델을 활용하여 횡경사 유무에 관계 없이 견실한 성능을 보장하는 제동기반 요 모멘트 제어시스템을 개발하였다. 2자유도 single track 모델과 횡가속도 센서 계측 신호를 융합하여 새로운 기준 요레이트 모델을 설계하였고 이를 기반으로 요 모멘트 제어기를 설계하였다. 또한 외란 관측기를 적용하여 요레이트 동역학에 존재하는 차량 파라미터 오차를 보상하고 제어기의 성능을 개선하였다. 다자유도 차량동역학 해석 SW인 CARSIM을 이용하여 평지 및 횡경사 노면을 반영한 다양한 검증 시나리오 조건에서 제안된 제어기를 검증하였다. 그 결과 기준 차량모델에 횡가속도 계측 신호를 반영하고 외란 관측기를 통해 모델 파라미터 오차를 보상하는 것을 특징으로 하는 새롭게 제안된 횡안정성 제어기가 도로 횡경사에 관계없이 다양한 주행상황에서 차량의 횡안정성을 견실하게 유지할 수 있음을 확인하였다.

• 한국전산유체공학회지
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• 제4권3호
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• pp.1-11
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• 1999

This paper describes the flow field analysis of an automobile with crosswind effects of 15°, 30° 45° and 60° of yaw angles. The governing equations of the 3-D incompressible Navier-Stokes equations are solved by the iterative time marching scheme. The Chimera grid technique has been applied to efficiently simulate the flow around the side-view mirror. The computated surface pressure coefficients have been compared with experimental results and a good agreement has been achieved. The A- and C-pillar vortex and other flow phenomena around the ground vehicle are evidently shown. The variation of aerodynamic coefficients of drag, lift, side force and moments with respect to yaw angle is systematically studied.

• 한국시뮬레이션학회:학술대회논문집
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• 한국시뮬레이션학회 2002년도 춘계학술대회논문집
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• pp.3-10
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• 2002

Yaw-checking and course-keeping ability in IMO's ship manoeuvrability standards is reviewed from the viewpoint of safe operation. Three types of assumed series-ships, which have systematically different instability on course, are taken as tested models. The numerical simulation on Z-test is carried out in order to examine the correlation between known manoeuvrability and various kinds of overshoot angle. Then simulator experiments are executed with series-ships in situation of curved, narrow of waterway by five pilots in order to examine the correlation between known manoeuvrability and degree of manoeuvring difficulty. Three kinds of IMO's criterion concerning yaw-checking and course-keeping ability are discussed and new criteria are proposed.

• 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.

• 한국가시화정보학회지
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• 제17권2호
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• pp.32-38
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• 2019

A comparison study between computational-fluid-dynamics simulation and wind tunnel test for a megawatt-class wind turbine is conducted. For the study, flow-field in wake, basic aerodynamic performance, and effect of the yaw error for a 1/86 scaled-down model of the NREL offshore 5 MW wind turbine are numerically calculated using commercial software "FloEFD" with $k-{\varepsilon}$ turbulence model. The computed results are compared to the wind tunnel test performed by the constant-velocity mode for the model. It is shown that discrepancy are found between the two results at lower tip-speed ratio and higher yaw angle, however, the velocity-defection distribution in the wake, the torque coefficient at moderated and high tip-speed ratios are in good agreement with the wind tunnel test.