Lateral and Longitudinal Control of Self-driving Car with Enhanced Trajectory tracking using Direct Yaw Stability Control

Abstract

In the present study of self-driving car motion planning and control, the primary focus is on velocity tracking and trajectory tracking. Although, many studies deal with velocity and trajectory tracking separately, during trajectory tracking yaw stability is hardly considered. In the present research, a fusion of the direct yaw stability control with lateral-longitudinal control in velocity and trajectory tracking for self-driving cars is studied. Considering vehicle dynamics, the velocity and trajectory tracking can be associated with lateral and longitudinal control of the car. In longitudinal control, a variable control structure with a sliding mode method has been incorporated. To carry out velocity tracking, the overall driving force is achieved against the error in velocity. In lateral control for trajectory tracking, a linear time-varying model predictive control (MPC) technique is employed to calculate the desired front wheel angle. Additionally, to upgrade the reliability and control of the longitudinal-lateral motion, a combined control framework is initiated. On this principle, to provide better yaw stability of the car while trajectory tracking, the driving force of the tire is assigned rationally by employing the direct yaw moment control. Simulation results give valuable evidence that the suggested control strategy is satisfactory in tracking the reference trajectory and velocity thereby improving the stability and the performance of the car