• 전력전자학회:학술대회논문집
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• 전력전자학회 2008년도 하계학술대회 논문집
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• pp.280-282
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• 2008

본 논문은 자동차용 능동 전륜 조향 제어 시스템을 소개한다. 능동 전륜 조향 장치는 조향의 편의성과 안정성을 위하여 조향비를 가변하거나 유사시 능동적으로 전자 제어 유닛(Electronic Control Unit : ECU)이 액추에이터를 제어해 주는 시스템이다. 최근 전자 샤시 시스템의 개발 추세인 샤시 통합 제어 관점에서 능동 전륜 조향 장치의 역할을 설정하고 성능 만족을 위한 제어기 구조에 관하여 설명한다. 설계된 제어 시스템을 3,300cc급 대형 승용차에 적용하여 그 유용성을 검증하였다.

• 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.

• 한국기계가공학회지
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• 제21권5호
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• pp.22-27
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• 2022

An integrated front steering system and front brake system (FSFB) is developed to improve the stability and controllability of an SUV. The FSFB simultaneously controls the additional steering angle and front brake pressure. An active front steering system (AFS) and an active front brake system (AFB) are designed for comparison. The results show that the FSFB enhances the lateral stability and controllability regardless of road and running conditions compared to the AFS and AFB. As a result, the yaw rate of the SUV tracks the reference yaw rate, and the side slip angle decreases. In addition, brake pressure control is more effective than steering angle control in improving the stability and steerability of the SUV on a slippery road. However, this deteriorates comfort on dry or wet asphalt.

• 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.

• 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.

• 대한기계학회논문집A
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• 제39권5호
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• pp.527-534
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• 2015

본 논문에서는 능동 전륜 조향장치(AFS)에 의한 횡력의 크기가 제한된 상황에서 자세 제어장치(ESC)와 능동 전륜 조향(AFS)을 이용한 통합 새시 제어기의 최적 요모멘트 분배 방법을 제안한다. 차량을 안정화시키는데 필요한 제어 요모멘트는 슬라이딩모드 제어이론을 이용하여 구한다. 가중 역행렬 기반 제어 할당 방법을 이용하여 제어 요모멘트를 ESC의 제동력과 AFS의 추가 조향각으로 분배한다. 저마찰 노면에서 AFS에 의한 횡력이 물리적 최대값을 초과하는 경우 제어 요모멘트를 제대로 만들어내지 못하므로 가중 역행렬 기반 제어 할당 방법을 이용하여 AFS에 의한 횡력의 크기를 제한하고 ESC의 제동력으로 부족한 제어 요모멘트를 보상하는 방법을 제안한다. 차량 시뮬레이션 패키지인 $CarSim^{(R)}$에서 시뮬레이션을 수행하여 AFS에 의한 횡력이 물리적 최대값을 초과하는 경우 제안된 방법이 차량의 조종 안정성과 횡방향 안정성을 향상시킨다는 사실을 검증했다.

• 대한기계학회논문집A
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• 제40권1호
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• pp.103-111
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• 2016

본 논문에서는 차량의 횡방향 안정성을 향상시키기 위해 자세 제어 장치(ESC)와 능동 전륜 조향(AFS)을 이용하는 통합 새시 제어의 적응 가변 가중치 조절 방법을 제안한다. 제어기 설계 방법론을 적용하여 차량을 안정화시키는데 필요한 제어 요 모멘트를 구한 후 이를 가중 역행렬 기반 제어 할당 방법(WPCA)을 이용하여 ESC 의 제동력과 AFS 의 추가 조향각으로 분배한다. 저마찰 노면에서는 차량의 속도가 높다면 횡슬립각이 증가하여 횡방향 안정성이 저하되므로 이를 방지하기 위해 WPCA 의 가변가중치를 상황에 따라 조절하는 방법을 제안한다. 차량 시뮬레이션 패키지인 CarSim 에서 시뮬레이션을 수행하여 제안된 방법이 통합 섀시 제어기의 횡방향 안정성을 향상시킨다는 사실을 검증한다.

• 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.

• 한국자동차공학회논문집
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• 제22권6호
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• pp.59-67
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• 2014

A numerical model and a controller of Active Front wheel Steer (AFS) system are designed in this study. The AFS model consists of four sub models, and the AFS controller uses sliding mode control and PID control methods. To test this model and controller an Integrated Dynamics Control with Steering (IDCS) system is also designed. The IDCS system integrates an AFS system and an ARS (Active Rear wheel Steering) system. The AFS controller and IDCS controller are compared under several driving and road conditions. An 8 degree of freedom vehicle model is also employed to test the controllers. The results show that the model of AFS system shows good kinematic steering assistance function. Steering ratio varies depends on vehicle velocity between 12 and 24. Kinematic stabilization function also shows good performance because yaw rate of AFS vehicle tracks the reference yaw rate. IDCS shows improved responses compared to AFS because body side slip angle is also reduced. This result also proves that AFS system shows satisfactory result when it is integrated with another chassis system. On a split-m road, two controllers forced the vehicle to proceed straight ahead.