Robust Vehicle Stability Control Using Smooth Sliding Mode and Tire Slip-Based Dynamic Control Allocation in ESC Systems

Abstract

This paper presents a comprehensive study on a chattering-free sliding mode control designed to enhance vehicle lateral stability. The proposed architecture is composed of three main: an upper controller, a control allocation, and a lower controller. In the upper controller, using a smooth integral sliding mode, the desired yaw moment is designed and to guarantee the robust performance in the presence of uncertainties. In the middle layer, a dynamic control allocation based on the Lyapunov function is proposed for the distribution of desired longitudinal tire slip, which guarantees the convergence of them to the optimal set and also the asymptotic stability. Finally, in the lower layer, using the sliding mode controller, the brake torque is designed to track the longitudinal slip obtained from the dynamics control allocation. The main feature of the proposed control is considering practical considerations in terms of computational load in the control allocation layer, and also the compatibility of the designed ESC control with production vehicles due to the design of control allocation based on longitudinal slip and the use of ABS system based on longitudinal tire slip control. The 10-degree-of-freedom vehicle dynamics model is validated with CarSim and the simulation results for the DLC steering scenario show its effectiveness in terms of eliminating chattering, tracking accuracy compared to the conventional sliding mode control.