• 한국자동차공학회논문집
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• 제4권6호
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• pp.39-51
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• 1996

In the turning maneuver of the vehicle, its motion is mainly dependent on the genuine steering characteristics in view of the directional stability for stable turning ability. The under steer vehicle has an ability to maintain its own directonal performance for unknown external disturbances to some extent. From a few years ago, in order to acquire the more enhanced handling performance, some types of four wheel steering vehicle were considered and constructed. And, various rear wheel control logics for external disturbances has not been suggested. For this reason, in this posed rear wheel control logic is based on the yaw rate feed back type and is slightly modified by an yaw rate tuning factor for more stable turning performance. And an external disturbance is defined as a motivation of the additional yaw rate in the center of gravity by an uncertain input. In this study, an external disturbance is applied to the vehicle as a form of the additional yawing moment. Finally, the proposed rear wheel control logic is tested on the multi-body analysis software(ADAMS). J-turn and double lane change test are performed for the validation of the control logic.

• 대한기계학회논문집A
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• 제41권7호
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• pp.591-597
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• 2017

이 논문은 횡방향 안정성 및 조향성능 개선을 위한 차량 통합운동제어시스템(IDCB)의 개발에 관한 것이다. IDCB의 개발을 위하여 8자유도의 차량 모델 및 비선형 관측기를 설계하였다. 퍼지 로직 제어 방법 및 슬라이딩 모드 제어 방법을 이용하여 전륜 및 후륜의 제동압력을 독립적으로 제어하여 차량의 요 속도 및 횡방향 미끄러짐 각이 목표값을 추종하도록 하였다. 결과를 살펴보면 비선형 관측기는 만족할 만한 수준의 관측 결과를 보여주었다. 개발된 IDBC는 다양한 노면 조건 및 운전 조건에서 요속도 및 횡방향 미끄러짐 각이 목표값을 잘 추종하도록 하여 차량의 횡방향 안정성 및 조향성을 개선시키는 것을 확인할 수 있다.

• 한국자동차공학회논문집
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• 제22권1호
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• pp.65-70
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• 2014

An Integrated Dynamics Control system with four wheel Steering (IDCS) is proposed and analysed in this study. It integrates and controls steer angle of front and rear wheel simultaneously to enhance lateral stability and steerability. An active front steer (AFS) system and an active rear steer (ARS) system are also developed to compare their performances. The systems are evaluated during brake maneuver and several road conditions are used to test the performances. The results showed that IDCS vehicle follows the reference yaw rate and reduces side slip angle very well. AFS and ARS vehicles track the reference yaw rate but they can not reduce side slip angle. On split-${\mu}$ road, IDCS controller forces the vehicle to go straight ahead but AFS and ARS vehicles show lateral deviation from centerline.

• 한국자동차공학회논문집
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• 제21권2호
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• pp.72-80
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• 2013

This study is to develop and evaluate an AFS and an ARS controllers to enhance lateral stability of a vehicle. A sliding mode control (SMC) and a fuzzy logic control (FLC) methods are applied to calculate the desired additional steering angle of AFS equipped vehicle or desired rear steer angle of ARS equipped vehicle. To validate AFS and ARS systems, an eight degree of freedom, nonlinear vehicle model and an ABS controllers are also used. Several road conditions are used to test the performances. The results showed that the yaw rate of the AFS and the ARS vehicle followed the reference yaw rate very well within the adhesion limit. However, the AFS improves the lateral stability near the limit compared with the ARS. Because the SMC and the FLC show similar vehicle responses, performance discrimination is small. On split-${\mu}$ road, the AFS and the ARS vehicle had enhanced the lateral stability.