• Transactions of the Korean Society of Automotive Engineers
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• v.8 no.4
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• pp.194-201
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• 2000

It is called vehicle pull when a vehicle drifts in the lateral direction under the straight-ahead motion with no steering or external input. Recently vehicle pull draws attention as one of the critical evaluation items from the customers on the vehicle quality. It is generally recognized that the vehicle pull is complex phenomena due to internal and external factors. In this paper the relations between vehicle pull and ire were investigated through close survey on the road test results from the final inspection of car manufactures. Through this investigation the factors are identified which play an important role in causing vehicle pull problem.

• Journal of the Korean Society for Precision Engineering
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• v.20 no.11
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• pp.91-99
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• 2003

When the driver suddenly depresses the brake pedal under critical conditions, the desired trajectory of the vehicle can be changed. In this study, the vehicle dynamics and fuzzy logic controller are used to control the vehicle trajectory. The dynamic vehicle model consists of the engine, the rotational wheel, chassis, tires and brakes. The engine model is derived from the engine experimental data. The engine torque makes the wheel rotate and generates the angular velocity and acceleration of the wheel. The dynamic equation of the vehicle model is derived from the top-view vehicle model using Newton's second law. The Pacejka tire model formulated from the experimental data is used. The fuzzy logic controller is developed to compensate for the trajectory error of the vehicle. This fuzzy logic controller individually acts on the front right, front left, rear right and rear left brakes and regulates each brake torque. The fuzzy logic controlling each brake works to compensate for the trajectory error on the split - $\mu$ road conditions follows the desired trajectory.

• Transactions of the Korean Society of Automotive Engineers
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• v.13 no.1
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• pp.76-82
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• 2005

In this paper, validation of Driver Steering Model has been conducted. The comparison between the simulation model and vehicle test results shows that the model is very feasible for describing combined human driver and actual vehicle dynamic behaviors. The 3D vehicle model is consisted of 6-DOF sprung mass and 4-quarter car model for vehicle body dynamics. Powertrain model including differential gear and Pacejka tire model are applied. The driver steering model is also validated with vehicle test result. The driver steering model is based on angle and displacement error from the desired path, recognized by driver.

• Structural Engineering and Mechanics
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• v.15 no.1
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• pp.1-19
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• 2003

This paper presents the formulation of a new bridge-vehicle system with validation using the field data. Both pitching and twisting modes of the vehicle are considered in the contribution of the dynamic effects in the bridge responses. A heavy vehicle was hired as a control vehicle with known axle weight, axle spacing and spring coefficients. The measured responses were generated from the control vehicle running at a particular speed at a test span at Ma Tau Wai Flyover. The measured responses were acquired using strain gauges installed beneath the girder beams of the test bridge. The simulated responses were generated using BRVEAN that is a self-developed program based on the proposed bridge-vehicle system. The validation shows that the bridge model is valid for representing the test bridge and the governing equations are valid for representing the motion of moving vehicles.

• Computers and Concrete
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• v.5 no.5
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• pp.503-508
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• 2008

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2012.04a
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• pp.305-306
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• 2012

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2013.10a
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• pp.531-532
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• 2013

• Transactions of the Korean Society of Mechanical Engineers A
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• v.27 no.5
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• pp.666-672
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• 2003

This paper presents a design of the controller for vehicle lateral dynamics using active yaw moment. Vehicle lateral motion is incorporated with directional controllability and stability. These are conflicting each other from the view of vehicle handling performance. To compromise the trade-off between these two aspects, we suggest a new control algorithm based on the sliding mode with time-varying switching surface according to the body side slip angle. The controller can deal with the nonlinear region in vehicle driving condition and be robust to the parameter uncertainties in the plant model. Control performance is evaluated from the simulation for the vehicle of real parameters on the road with various tire-road frictions.

• 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.

• Journal of the Korean Society for Precision Engineering
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• v.23 no.6 s.183
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• pp.72-80
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• 2006

Electric Power Steering (EPS) mechanism has become widely equipped in passenger vehicle due to the increasing environmental concerns and higher fuel efficiency. This paper describes the development of concurrent simulation technique and simulation integration technique of EPS control system with a dynamic vehicle system. A full vehicle model interacting with EPS control algorithm was concurrently simulated on a single bump road condition. The dynamic responses of vehicle chassis and steering system resulting from road surface impact were evaluated and compared with proving ground experimental data. The comparisons show reasonable agreement on tie-rod load, rack displacement, steering wheel torque and tire center acceleration. This concurrent simulation capability was employed fur EPS performance evaluation and calibration as well as for vehicle handling performance integration and synthesis.