• 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.

• 한국항공우주학회지
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• 제38권1호
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• pp.42-47
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• 2010

본 논문에서는 모멘텀 교환장치인 휠을 사용하는 위성의 내고장 제어 문제를 다루고 있다. 2개의 휠만이 정상인 경우에 위성의 자세를 제어하는 것에 대한 연구결과를 제시한다. 두 가지 다른 형상의 휠 조합을 고려하였다. 요 축을 직접적으로 제어할 수 없는 조합에 대해서는 롤 각속도를 의사 입력으로 이용해서 원하는 요 각속도를 구현하였다. 결과적으로 세 축의 각속도 모두를 안정화시키고, 두 축의 자세각을 원하는 값에 수렴하도록 제어 할 수 있었다.

• 대한기계학회논문집A
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• 제23권6호
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• pp.931-942
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• 1999

This paper develops a 3 DOF vehicle model which includes lateral, roll and yaw motion to study a 4WS vehicle. The model is used for the simulation of a 4WS vehicle behavior, and to derive a control algorithm for rear wheel steering. This paper uses a feedforward plus feedback control scheme to compute a rear wheel steering angle. The feedforward control scheme for computing the first rear wheel steering angle uses a gain which is acquired by multiplying a proper value on a gain to maintain a zero sideslip angle. The feedback control scheme for computing the second rear wheel steering angle uses fuzzy logic and model following control scheme. A linear 2 DOF model is used as a reference model for model following control, and is derived from the developed 3 DOF model by neglecting sprung mass roll motion. A reference state variable is yaw rate, and is computed using the linear 2 DOF model. J-turn and lane change maneuver simulation are performed to show the effectiveness of the developed control scheme. The simulation results show that the 4WS vehicle with the developed control scheme has much better performance in yaw rate, lateral acceleration, roll angle, and sideslip angle than the 2WS vehicle. Also, the results show that the performance of the developed control is close to the one of an optimal control which assumes all states are perfect.

• 융합신호처리학회논문지
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• 제22권4호
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• pp.171-178
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• 2021

카라반은 외부의 물리적 요인에 쉽게 영향을 받아 탑승자에게 위험한 상황을 초래하는 경우가 많다. 따라서 탑승자의 안정성을 확보하기 위해 스웨이 현상을 사전에 예방할 수 있는 스웨이 저감 장치를 개발할 필요성이 있다. 본 논문에서는 견인차량과 카라반 사이의 Hitch angle을 최소화하는 것을 목표로 한다. 구체적으로는 견인차량과 카라반 각각에 장착된 IMU 센서를 통해 카라반의 초기 불안정성을 감지하고, PID 제어기를 이용하여 Hitch angle, Hitch yaw rate가 Desired hitch angle, Desired hitch yaw rate에 수렴할 수 있도록 제어 값을 산출한다. 산출된 제어 값에 따라 카라반 좌우 브레이크에 다른 제동토크를 생성하여 분배하고 제어한다. 주행 실험을 통해 스웨이 저감 장치의 성능을 검증한 결과, 제어하지 않은 경우보다 Hitch angle이 감소한 것을 확인할 수 있었고, 횡 방향 안정성 향상률은 제어 전에 비해 78.9% 향상된 것을 확인하였다.

• 한국군사과학기술학회지
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• 제14권6호
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• pp.1026-1030
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• 2011

This paper presented here contains development of variable stability system(VSS) control laws for the KIFS (Korean In-Flight Simulator) aircraft to simulate the dynamics of F-16 aircraft. Development of VSS Control law for pitch rate, roll rate, yaw rate simulation for three specified flight conditions using Model Following Technique with rate feedback autopilot for stability provision. The direct lift force controller was also added to the developed VSS control law to simulate the pitch rate and normal g-load simultaneously. The simulation results show high accuracy of F-16 aircraft's pitch, roll, yaw rate and g-load simulation.

• International Journal of Automotive Technology
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• 제8권3호
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• pp.299-308
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• 2007

This study proposes a two-layer hierarchical control system that integrates active front wheel steering and four wheel braking torque control to improve vehicle handling performance and stability. The first layer is a robust model matching controller (R-MMC) based on linear matrix inequalities (LMIs), which optimizes an active front steering angle compensation and a desired yaw moment control, and calculates reference wheel slip for the target wheel according to the desired yaw moment. The second layer is a moving sliding mode controller (MSMC) that can track the reference wheel slip in a predetermined time by commanding proper braking torque on the target wheel to achieve the desired yaw moment. Since vehicle sideslip angle measurement is difficult to achieve in practice, a sliding mode observer (SMO) that requires only vehicle yaw rate as the measured input is also developed in this study. The performance and robustness of the SMO and the integrated control system are demonstrated through comprehensive computer simulations. Simulation results reveal the satisfactory tracking ability of the SMO, and the superior improved vehicle handling performance, stability and robustness of the integrated control vehicle.

• 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.

• 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.

• 대한기계학회논문집A
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• 제24권8호
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• pp.1899-1909
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• 2000

This paper proposes a new $H_{\infty}$ yaw moment control scheme using brake torque switching for improving vehicle performance and stability especially in high speed driving. In the scheme, one wheel is selected, depending on the vehicle states, at which a brake torque for control is applied. Steering angles are modeled as a disturbance to the system and the $H_{\infty}$ controller is designed to minimize the difference between the performance of the vehicle and that of the desired model. Its performance robustness as well as stability robustness to system parameter variations is assured through ${\mu}$-analysis. Various simulations with a nonlinear 8-DOF vehicle model show that proposed controller enhances the vehicle performance and stability under disturbances and parameter variations as well as under the normal driving condition.

• 전기학회논문지
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• 제56권7호
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• pp.1218-1223
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• 2007

A surface micro machined angular rate sensor utilizing a vibrating MEMS structure on a silicon has been developed. These tuning fork angular rate sensors are extremely rugged, inherently balanced, and easy to fabricate. The device is fabricated using a temperature compensation method based on automatic gain control technique. A linearity of approximately 0.6%, limited by the on-chip electronics has been obtained with this new sensor. Tests of the sensor demonstrate that its performance is equivalent to that required for implementation of a yaw control system. Vehicle handling and safety are substantially improved using the sensor to implement yaw control.