• Journal of the Korean Society of Manufacturing Process Engineers
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• v.21 no.5
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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.

• Transactions of the Korean Society of Automotive Engineers
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• v.5 no.4
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• pp.29-38
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• 1997

In this paper, brake steering performance of electric-driven special-purpose vehicles is investigated. A 14 DOF model is developed considering nonlinear character- istics of the suspension and tire. Based on the model, cornering performance is analyzed for brake steering, acceleration steering and pivoting, respectively. Simulation results are obtained based on the developed SIMULINK module. This analysis about the non steady state cornering performance is particularly important for armored vehicles because the projected route of the vehicle at emergency should be predicted accuracy.

• Journal of the Korean Society for Precision Engineering
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• v.19 no.11
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• pp.65-74
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• 2002

This paper examines the usefulness of a Brake Steer System (BSS), which uses differential brake forces for steering intervention in the context of Intelligent Transportation Systems (ITS). In order to help the car to turn, a yaw moment can be achieved by altering the left/right and front/rear brake distribution. This resulting yaw moment on the vehicle affects lateral position thereby providing a limited steering function. The steering function achieved through BSS can then be used to control lateral position in an unintended road departure system. A 8-DOF nonlinear vehicle model including STI tire model will be validated using the equations of motion of the vehicle. Then a controller will be developed. This controller, which will be a PID controller tuned by Ziegler-Nichols, will be designed to explore BSS feasibility by modifying the brake distribution through the control of the yaw rate of the vehicle.

• International Journal of Precision Engineering and Manufacturing
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• v.5 no.3
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• pp.26-34
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• 2004

This paper examines the usefulness of a Brake Steer System(BSS), which uses differential brake forces for steering intervention in the context of Intelligent Transportation Systems(ITS). In order to help the car to turn, a yaw moment control was achieved by altering the left/right and front/rear brake distribution. This resulting yaw moment on the vehicle affects lateral position thereby providing a limited steering function. The steering function achieved through BSS was used to control lateral position in an unintended road departure system. A 8-DOF nonlinear vehicle model including STI tire model was validated using the equations of motion of the vehicle. Then a controller was developed. This controller, which is a PID controller tuned by Ziegler-Nichols, is designed to explore BSS feasibility by modifying the brake distribution through the control of the yaw rate of the vehicle.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2002.05a
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• pp.233-237
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• 2002

Vehicle Dynamics Control(VDC) has been a breakthrough and become a new terminology for the safety of a driver and improvement of vehicle handling. This paper examines the usefulness of a brake steer system (BSS), which uses differential brake forces for steering intervention in the context of VDC. In order to help the car to turn, a yaw moment can be achieved by altering the left/light and front/rear brake distribution. The steering function achieved through BSS can then be used to control lateral position in an unintended road departure system. A 8-DOF non-linear vehicle model including STI tire model will be validated using the equations of motion of the vehicle, and the non-linear vehicle dynamics. Since Fuzzy logic can consider the nonlinear effect of vehicle modeling, Fuzzy controller is designed to explore BSS feasibility, by modifying the brake distribution through the control of the yaw rate of the vehicle. The control strategies developed will be tested by simulation of a variety of situation; the possibility of VDC using BSS is verified in this paper.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2011.04a
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• pp.401-406
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• 2011

The abnormal vibration from the BTV(Brake Torque Variation) and DTV(Disc Thickness Variation) is transferred to the suspension and steering system during braking. In this paper, judder simulation is carried out using multi-body dynamic analysis program to analyze the relation of the judder and transfer mechanism which is composed of the suspension and steering system. In order to analyze the brake judder transfer system, the full vehicle model was composed with rigid body, non-linear bushing, non-linear constraints and joints. Full vehicle model analysis was compared by actual vehicle judder test and sensitivity analysis of the suspension system is carried out.

• Transactions of the Korean Society of Automotive Engineers
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• v.15 no.6
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• pp.120-127
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• 2007

This paper describes the development of a nonlinear observer for four wheel steer (4WS) vehicle. An observer is designed to estimate the vehicle variables difficult to measure directly. A brake yaw motion controller (BYMC), which uses a PID control method, is also proposed for controlling the brake pressure of the rear and inner wheels to enhance lateral stability. It induces the yaw rate to track the reference yaw rate, and it reduces a slip angle on a slippery road. The braking and steering performances of the anti-lock brake system (ABS) and BYMC are evaluated for various driving conditions, including straight, J-turn, and sinusoidal maneuvers. The simulation results show that developed ABS reduces the stopping distance and increases the longitudinal stability. The observer estimates velocity, slip angle, and yaw rate of 4WS vehicle very well. The results also reveal that the BYMC improves vehicle lateral stability and controllability when various steering inputs are applied.

• Journal of the Korean Society for Precision Engineering
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• v.20 no.5
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• pp.82-91
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• 2003

Vehicle dynamics control (VDC) has been a breakthrough and become a new terminology for the safety of a driver and improvement of vehicle handling. This paper examines the usefulness of a brake steer system (BSS), which uses differential brake forces for steering intervention in the context of VDC, In order to help the car to turn, a yaw moment can be achieved by altering the left/right and front/rear brake distribution. The steering function achieved through BSS can then be used to control lateral position in an unintended road departure system. An 8-DOF non-linear vehicle model including STI tire model will be validated using the equations of motion of the vehicle, and the non-linear vehicle dynamics. Since fuzzy logic can consider the nonlinear effect of vehicle modeling, fuzzy controller is designed to explore BSS feasibility, by modifying the brake distribution through the control of the yaw rate of the vehicle. The control strategies developed will be tested by simulation of a variety of situation; the possibility of VDC using BSS is verified in this paper.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.28 no.8 s.227
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• pp.1125-1134
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• 2004

This paper presents a mathematical model which is about the dynamics of not only a two wheel steering vehicle but a four wheel steering vehicle. A sliding mode ABS control strategy and PID rear wheel control logic are developed to improve the brake and cornering performances, and enhance the stability during emergency maneuvers. The performances of the controllers are evaluated under the various driving road conditions and driving situations. The numerical study shows that the proposed full car model is sufficient to accurately predict the vehicle response. The proposed ABS controller reduces the stopping distance and increases the vehicle stability. The results also prove that the ABS controller can be employed to a four wheel steering vehicle and improves its performance. The four wheel steering vehicle with PID rear wheel controller shows increase of stability when a vehicle speed is high and sharp cornering maneuver when a vehicle speed is low compared to that of a two wheel steer vehicle.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2001.11a
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• pp.439-443
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• 2001

The steering wheel vibrations such as shimmy, brake judder and shake are affected by the vibration characters of steering and suspension. For the analysis of shimmy, nonuniformities of tire can be considered the major sources. This study investigates unbalances and uniformities of tire in which the lateral force variation is highly correlated with shimmy. The hardness of suspension bushes can be modified to change the dynamic behavior of suspension that is effective to reduce the sensitivity of shimmy.