Vehicle Stability Control through Optimized Coordination of Active Rear Steering and Differential Driving/Braking

In this article, a hierarchical coordinated control algorithm for integrating active rear steering and driving/braking force distribution (ARS+D/BFD) was presented. The upper-level control was synthesized to generate the required rear steering angle and external yaw moment by using a sliding-mode controller. In the lower-level controller, a control allocation algorithm considering driving/braking actuators and tire forces constraints was designed to assign the desired yaw moment to the four wheels. To this end, an optimization problem including several equality and inequality constraints were defined and solved analytically. Finally, computer simulation results suggest that the proposed hierarchical control scheme was able to help to achieve substantial enhancements in handling performance and stability. Moreover, the comparison between ARS+D/BFD and AFS+D/BFD (active front steering and driving/braking force distribution) by using the proposed controller was presented and analyzed.