• Transactions of the Korean Society of Mechanical Engineers A
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• v.41 no.7
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• pp.591-597
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• 2017

This study is to develop a vehicle Integrated Dynamics Control System(IDCB) that can stabilize the lateral dynamics and maintain steerability. To accomplish this task, an eight degree of freedom vehicle model and a nonlinear observer are designed. The IDCB independently controls the brake systems of four wheels with a fuzzy logic control and a sliding model control. The result shows that the nonlinear observer produced satisfactory results. IDCB tracked the reference yaw rate and reduced the body slip angle under all tested conditions. It indicates that the IDCB enhanced lateral stability and preserved steerability.

• Transactions of the Korean Society of Mechanical Engineers
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• v.9 no.4
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• pp.509-517
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• 1985

작업 공간내에서 원하는 속도와 가속도로, 주어진 경로를 따라 이동하는 k차원 좌표계를 구성하고, 메니퓰레이터의 운동 방정식을 이 좌표계로 변환하여 운동 경로에 대한 선형화 식을 구하였다. 이 시스템의 입력을 변위와 속도의 함수로 정의한 후 안정성을 고려하여 이득을 결정하여 비례-적분제어 시스템을 구성하였다. 이와 같이 구한 적응 제어 알고리즘은 메니퓰레이터의 동적 특성에 대한 정확한 지식을 요하지 않고 또 계산이 간단하여 실시간 응용이 가능하다. 예로서 3차원 공간상의 반경 10cm의 원궤도에 적용하였을 때 최대 오차는 대략 1mm이었으며 상황 변화에 무감각함을 보였다.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.24 no.8 s.179
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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.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.38 no.11
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• pp.1291-1297
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• 2014

This paper proposes integrated chassis control (ICC) with electronic stability control (ESC) and active rear steering (ARS). Direct yaw moment control is used to generate a control yaw moment. A weighted pseudo-inverse-based control allocation (WPCA) method is adopted to distribute the control yaw moment into tire forces, generated by ESC and ARS. Simulation-based tuning of variables weights in the WPCA is used to enhance the yaw moment distribution performance. Simulations using the vehicle simulation software $CarSim^{(R)}$ show that the proposed ICC is effective in improving maneuverability and lateral stability.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.41 no.10
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• pp.967-974
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• 2017

In this paper, a differential-braking-based yaw moment control system was developed to guarantee robust performance against road bank angle. A new target yaw rate model was established by combining the signal from a lateral acceleration sensor and 2-DOF single track model. In addition, a disturbance observer was utilized to take into account parameter uncertainties in yaw dynamics and to improve robust performance of the controller. CARSIM, which is a multi-DOF vehicle dynamic simulation tool, was used to verify the performance of the proposed controller in various driving scenarios. The simulation results indicate that the stability of the vehicle was robustly maintained by the controller, which is characterized by the reflection of the signal of a lateral acceleration sensor signal and by the compensation of the errors in the model parameters via the disturbance observer.

• Aerospace Engineering and Technology
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• v.7 no.2
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• pp.88-94
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• 2008

In this study, triaxial velocity is analyzed for COMS(Communication, Ocean and Meteorological Satellite) configuration, which is generated when thrusters are used to dump wheel momentum. Since COMS is designed to periodically change the thruster set in order to uniformly decrease the performance of thrusters, triaxial velocity would be different during the change of thruster set. So, the triaxial velocity generated due to the change of thruster set is optimized.

• The Transactions of the Korean Institute of Power Electronics
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• v.6 no.2
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• pp.149-157
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• 2001

A nonlinear speed control for a permanent magnet synchronous motor (PMSM) using a simple disturbance estimation technique is presented. By using a feedback linearization scheme, the nonlinear motor model can be linearized in a controllable canonical form, and the desired speed dynamics can be obtained based on the linearized model. This technique, however, gives an undesirable output performance under the mismatch of the system parameters and load conditions. To cancel disturbance by parameter variation, the controller parameters will be estimated by using a disturbance observer theory where the disturbance torque and flux linkage are estimated. since only the two reduced order observers are used for the parameter estimations, the observer designs are considerably simple and the additional load for computation of the controller is negligibly small. The proposed control scheme is implemented on a PMSM using DSP TMS320C31 and the effectiveness is verified through the comparative simulations and experiments.

• Transactions of the Korean Society of Automotive Engineers
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• v.22 no.1
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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.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2011.04a
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• pp.206-211
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• 2011

In this paper, a control algorithm for the improvement of yaw and velocity stability of electrical vehicle with two or four in-wheel motors is proposed. The vehicle is modeled with independently operative in-wheel motor wheels. Different frictions on the wheels are regarded as disturbances, which causes driving instability. In this situation the proposed algorithm enables stabilizing the yaw motion and velocity of vehicle simultaneously. The proposed PID controller is composed with two techniques, which enhance the disturbance reject and point tracking performances. One is nonlinear gain function and the other one is improved integral controller operating as time based weight function. Simulation is conducted to reveal its efficient performance.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.21 no.11
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• pp.554-560
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• 2020

In the manufacturing process of flat panel displays, a high-precision planar motion stage is used to position a specimen. Stages of this type typically use frictionless linear motors and air bearings, and laser interferometers. Real-time dynamic correction of the yaw motion error is very important because the inevitable yaw motion error of the stage means a change in the specimen orientation. Gantry control is generally used to compensate for yaw motion errors. Flexure units that allow rotational motion are applied to the stage to apply this method to a stage using an air-bearing guide. This paper proposes a method to improve the constant speed motion performance of a H-type XY stage equipped with air bearing and flexure units. When applying the gantry control to the stage, including the flexure units, the cause of the mutual ripple generated from the linear motors is analyzed, and adaptive learning control is proposed to compensate for the mutual ripple. A simulation was performed to verify the proposed method. The speed ripple was reduced to approximately the 22 % level. The ripple reduction was verified by simulating the stage state where yaw motion error occurs.