• Transactions of the Korean Society of Mechanical Engineers A
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• v.30 no.10 s.253
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• pp.1276-1283
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• 2006

This study proposes two ESP systems which are designed to enhance the lateral stability of a vehicle. A BESP uses an inner rear wheel braking pressure controller, while a EBESP employs an inner rear wheel and front outer wheel braking pressure controller. The performances of the BESP and EBESP are evaluated for various road conditions and steering inputs. They reduce the slip angle and eliminate variation in the lateral acceleration, which increase the controllability and stability of the vehicle. However EBESP enhances the lateral stability and comfort. A driver model is also developed to control the steer angle input. It shows good performances because the vehicle tracks the desired lane very well.

• Journal of the Korean Society for Precision Engineering
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• v.23 no.2 s.179
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• pp.104-112
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• 2006

The influence of tire belt angle on the Plysteer Residual Aligning Torque(PRAT) and the cornering stiffness by the FEM has been studied. The PRAT is a performance factor of the tire about vehicle pull, and the cornering stiffness has relation to vehicle steering response of outdoor test. To validate FE model for analysis, simulation data for both the static stiffness(vertical, lateral) and the PRAT have been compared with the experimental data. In addition to the characteristics of the PRAT and the cornering stiffness due to the tire belt angle, rolling and cornering contact characteristics have been studied. The tendency of the PRAT and the cornering stiffness due to the belt angle can be used as a guide line for the tire design in relation to vehicle pull and vehicle steering response.

• Transactions of the Korean Society of Automotive Engineers
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• v.19 no.4
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• pp.38-46
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• 2011

This paper presents roll angle estimator which used Kalman filter. Recently, the uses of the ELSD (Electronic Limited Slip Differential) and TVD(Torque Vectoring Differential) for vehicle yaw control are studied in many researches. However the roll angle can be negative effect of ELSD and TVD control. Therefore the information of roll angle can be used for vehicle yaw control. Moreover it can be used for rollover prevent control. Recently, most of the vehicles use lateral acceleration and yaw rate sensor. In this paper, design of Kalman filter which used lateral acceleration and yaw rate information is developed. In this paper, in order to verify the estimator ability, the CarSim and Matlab/Simulink are used.

• Proceedings of the KSME Conference
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• 2001.06b
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• pp.565-570
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• 2001

Vehicle dynamics control (VDC) system requires more information on driving conditions compared with ABS and/or TCS. In order to develop the VDC system, tire slip angles, vehicle side-slip angle, and vehicle lateral velocity as well as road friction coefficient are needed. Since there are not any cheap and reliable sensors, recent researches on parameter estimation have given rise to a number of parameter estimation techniques. This paper presents new vehicle model to estimate vehicle's yaw rate. This model is improved from the conventional 2 degrees of freedom vehicle model, so-called bicycle model, taking nonlinear effects into account. These nonlinear effects are: (i) tyre nonlinearity; (ii) lateral load transfer during cornering; (iii) variable gear ratio with respect to vehicle velocity. Estimation results are validated with the experimental results.

• Journal of Auto-vehicle Safety Association
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• v.5 no.1
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• pp.62-68
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• 2013

This paper describes development of 4 Wheel Drive (4WD) Electric Vehicle (EV) based driving control algorithm for severe driving situation such as icy road or disturbance. The proposed control algorithm consists three parts : a supervisory controller, an upper-level controller and optimal torque vectoring controller. The supervisory controller determines desired dynamics with cornering stiffness estimator using recursive least square. The upper-level controller determines longitudinal force and yaw moment using sliding mode control. The yaw moment, particularly, is calculated by integration of a side-slip angle and yaw rate for the performance and robustness benefits. The optimal torque vectoring controller determines the optimal torques each wheel using control allocation method. The numerical simulation studies have been conducted to evaluated the proposed driving control algorithm. It has been shown from simulation studies that vehicle maneuverability and lateral stability performance can be significantly improved by the proposed driving controller in severe driving situations.

• Transactions of the Korean Society of Automotive Engineers
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• v.22 no.4
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• pp.131-137
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• 2014

The SUV has a risk of rollover because of the highness of center of mass. In this paper the roll-behavior of a SUV in turning motion is analyzed. Dynamic model of the vehicle on the slope is developed and simulation is carried out using the software ADAMS/Car. The results show that the relational expression between the ground force acting on the tire and the roll motion is well established. It is also identified that the driving state of the vehicle becomes unstable at the lower or upper position of the slope.

• Transactions of the Korean Society of Automotive Engineers
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• v.13 no.5
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• pp.195-201
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• 2005

In conventional Vehicle Stability Control (VSC) System, a control threshold is designed by average driver characteristics. Despite the stabilizing effort, VSC causes redundancy to an expert driver. An advanced VSC which has flexibility on its control property is proposed in this study. By using lateral velocity estimator, a control threshold is determined on side slip angle and angular velocity phase plane. Vehicle planar motion model based sliding controller is modified with respect to various control thresholds. The performance of the proposed VSC algorithm has been investigated by human-in-the-loop simulation using a vehicle simulator. The simulation results show that the control threshold has to be determined with respect to the driver steering characteristics. A VSC with variable control thresholds would provide an improvement compared to a VSC with a constant threshold.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.17 no.4
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• pp.70-75
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• 2018

This paper describes an Integrate Dynamic Control system with Brake System (IDCB) for SUV vehicles. The system was developed to stabilize the lateral dynamics, maintain the steerability and improve the ride comfort on various roads. A fuzzy logic control method is used to design the IDCB. The performance of the IDCB is validated under different road and driving conditions. The results show that the IDCB tracks the reference yaw rate under all tested conditions; in addition, it reduces the body slip angle and roll angle. When a vehicle runs on a split-${\mu}$ road and a brake input is applied, the IDCB virtually eliminates the lateral dynamics. Thus, the IDCB improves the lateral stability, preserves the steerability and enhances the ride comfort of vehicles.

• Transactions of the Korean Society of Automotive Engineers
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• v.21 no.2
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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.

• Transactions of the Korean Society of Automotive Engineers
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• v.24 no.3
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• pp.310-318
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• 2016

The demands for vehicle safety systems such as ABS and ESC have been increased. Accurate vehicle state estimation is required to realized the abovementioned systems and tire-friction coefficient is crucial information. Estimation of lateral tire-road friction coefficient using pneumatic trail information is mainly dealt in this paper. Pneumatic trail shows unique characteristics according to the wheel side slip angle and these property is highly sensitive to vehicle lateral motion. The proposed algorithm minimizes the use of conventional tire models such as magic formula, brushed tire model and Dugoff tire model. The pure side slip maneuver, which means no longitudinal dynamics, is assumed to achieve the ultimate goal of this paper. A simulation verification using Carsim and Simulink is performed and the results show the feasibility of the proposed algorithms.