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

• Korean Journal of Computational Design and Engineering
• /
• v.7 no.1
• /
• pp.1-8
• /
• 2002

A Hotchkiss spring has been widely utilized for commercial vehicle. Usually, the Hotchkiss spring has non-linear characteristics, i.e. it has a piecewise spring stiffness as well as hysterisis phenomenon. Therefore, the modeling of the Hotchkiss spring requires many considerations to fulfill satisfactory vehicle kinematic and dynamic relationships. Also, the spring has difficulties in modeling for presenting contact mechanism. In this paper, the modeling technique for the Hotchkiss spring has been descried. The modeling covers non-linear characteristics as well as contact problems for multi-body dynamic simulation. The force-displacement results are compared with experimental and FEM ones. Also, the comparison between three link type leaf spring model and proposed one has been considered in this paper.

• International Journal of Ocean System Engineering
• /
• v.1 no.3
• /
• pp.120-135
• /
• 2011

This paper proposes a model based trajectory tracking control scheme for under-actuated underwater robotic vehicles. The difficulty in stabilizing a non-linear system using smooth static state feedback law means that the design of a feedback controller for an under-actuated system is somewhat challenging. A necessary condition for the asymptotic stability of an under-actuated vehicle about a single equilibrium is that its gravitational field has nonzero elements corresponding to non-actuated dynamics. To overcome this condition, we propose a continuous time-varying control law based on the direct estimation of vehicle dynamic variables such as inertia, damping and Coriolis & centripetal terms. This can work satisfactorily under commonly encountered uncertainties such as an ocean current and parameter variations. The proposed control law cancels the non-linearities in the vehicle dynamics by introducing non-linear elements in the input side. Knowledge of the bounds on uncertain terms is not required and it is conceptually simple and easy to implement. The controller parameter values are designed using the Taguchi robust design approach and the control law is verified analytically to be robust under uncertainties, including external disturbances and current. A comparison of the controller performance with that of a linear proportional-integral-derivative (PID) controller and sliding mode controller are also provided.

• Journal of the Korean Society of Manufacturing Process Engineers
• /
• v.11 no.5
• /
• pp.48-53
• /
• 2012

A non-linear vehicle model and an observer are designed to observe the yaw rate and the body side slip angle when a vehicle is turning maneuver in this study. The developed vehicle model is a full car model and has fourteen degree of freedom. A Luenberg observer is applied to develop the observer. The vehicle model is validated with a reference result and shows good accordance. The observer is tested on dry asphalt, wet asphalt and snow paved road. The results prove the performance of observer is robust and reliable.

• Proceedings of the Korean Geotechical Society Conference
• /
• 2006.03a
• /
• pp.552-561
• /
• 2006

The purpose of this study is to propose a pavement analysis system which considers dynamic effects resulted from the various vehicle speeds. Vehicle loading effects were estimated by loading frequency and dynamic loads under various vehicle speeds. In addition, a proposed analysis model takes the non-linear temperature using a predictive model for dynamic modulus in asphalt layer and the non-linear stress in the unbound material. To examine adequacy of existing multi-layer elastic analysis of non-linear temperature in asphalt layer and non-linear stress conditions in unbound material, this study divided layers of asphalt pavement structures with 10 layers in asphalt, 2 layers in subbase and 1 layer in subgrade. In order to verify the pavement analysis system that considers various speeds, deflections of pavement calculated using ABAQUS, a three dimensional finite element program, were compared with the results of field tests under various speeds.

• Proceedings of the Korean Society of Precision Engineering Conference
• /
• 2002.05a
• /
• pp.233-237
• /
• 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 IEEK Conference
• /
• 2009.05a
• /
• pp.216-218
• /
• 2009

This paper proposes an image processing algorithm to stabilize shaken scenes of UAV(Unmanned Aerial Vehicle) caused by vehicle self-vibration and aerodynamic disturbance. The proposed method stabilizes images by compensating estimated shake motion which is evaluated from global motion. The global motion between two continuous images modeled by 6 parameter warping model is estimated by non-linear square method based on Gauss-Newton algorithm with excluding outlier region. The shake motion is evaluated by subtracting the global motion from aerial vehicle motion obtained by averaging global motion. Experimental results show that the proposed method stabilize shaken scenes effectively.

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

• Journal of Auto-vehicle Safety Association
• /
• v.5 no.2
• /
• pp.11-16
• /
• 2013

This paper presents a unified control algorithm of independent braking and steering for collision avoidance. The desired motion of the vehicle in the yaw plane is determined using the probabilistic risk assessment method based on target state estimation. For the purpose of coordinating the independent braking and steering, a non-linear vehicle model has been developed, which describes the vehicle dynamics in the yaw plane in both linear and extended non-linear ranges of handling. A control allocation algorithm determines the control inputs that minimize the difference between the desired and actual vehicle motions, while satisfying all actuator constraints. The performance of the proposed control algorithm has been investigated via computer simulations conducted using the vehicle dynamics software CARSIM and Matlab/Simulink.

• Proceedings of the KIEE Conference
• /
• 2008.07a
• /
• pp.616-618
• /
• 2008

This paper propose nonlinear electromagnet suspension system model and defines electromagnet design specification of Maglev vehicle for transport system of semiconductor manufacturing line. The bandwidth of the acceleration sensor is defined and manufactured using i-mems technique acceleration sensor from this Nonlinear electromagnet suspension model. Through the simulation of non-linear model it was possible to compare the gain with the experiment to confirm the accuracy of the nonlinear suspension system. Till now mainly linear model has been used in many electromagnet suspension system, which results different gains in simulation and experiments. This more accurate non-linear model can be applied in many ways in designing electromagnet suspension systems.