Development of Coordinator for Optimal Tireforces Distribution for Vehicle Dynamics Control Considering Nonlinear Tire Characteristics

The Vehicle Dynamics Control (VDC) system is designed to enhance vehicle stability by effectively applying corrective yaw moments through differential brake forces during severe maneuvers. The VDC configuration primarily comprises two essential components: the supervisor and coordinators. The supervisor is responsible for determining appropriate corrective yaw moments, while the coordinators decide the tire forces necessary to achieve the desired corrective yaw moments. In modern times, various control schemes, such as model predictive controls, h-infinity controls, and relative controls, have been extensively investigated for the supervisors. However, in contrast, research concerning the coordinator component has not received much attention, resulting in relatively low research numbers. Most of the research has focused on the utilization of VDC coordinators that decide tire forces solely in proportion to corrective yaw moments. This approach leads to significant errors due to assumptions that do not account for the nonlinear characteristics of tires. In this research analysis, a coordinator considering nonlinear tire characteristics, such as the friction ellipse effect is presented. This crucial method of considering tire's nonlinear characteristics significantly enhances the accuracy of achieving the corrective yaw moment. Overall, the developed coordinator was validated through both simulations and experiments.