Mohammad Amin Saeedi - Assistant Professor, Department of Mechanical Engineering, Parand Branch, Islamic Azad University, Parand, Iran.

In this paper for handling improvement and lateral stability increment of a four-wheeled vehicle a new robust active control system is proposed. First, to establish an accurate model of the vehicle, a fourteen-degrees-of-freedom nonlinear dynamic model is developed. Next to control the lateral motion and yawing motion of the vehicle a new active steering control system designed based on a simplified two-degrees-of-freedom dynamic model. The main reason of using the active steering controller is to track the desired values of the yaw rate and lateral velocity. Also, sliding mode control method is used to design the control system. A complete stability analysis based on the Lyapunov theory is presented to guarantee closed-loop stability. Simulation results show that the controller improves the vehicle’s maneuverability, especially during severe double lane change maneuver in which intense instability occurs. More investigations demonstrate that the proposed control system can considerably improve vehicle maneuverability and path tracking under uncertainties.

Handling, Path Tracking, sliding mode control, Uncertainty