A new optimum method for sharing tire forces in electronic stability control system

Electronic Stability Control (ESC) is one of the most effective methods of controlling the Yaw moment in vehicles. This method is based on unequal distribution of tire forces (mainly braking forces) and is particularly effective when tire behavior is in nonlinear zone and loses its sensitivity to the steering input. While different approaches for evaluating the adequate Yaw moment have been developed, an approach based on Optimal Control theory has been utilized here. The main idea of this article is presenting an optimum method for evaluating the best distribution of longitudinal tire forces to generate the demanded yaw moment. This is the source of some important limitations in current ESC systems. This issue is done by solving an online NLP problem. While this problem is defined based on Pacejka combined tire model, the coupling of lateral and longitudinal tire forces has been considered and desired yaw moment is generated in an optimum way. Simulation results reveal the effectiveness and improvement in performance of ESC by the use of this method.