Direct-yaw-moment control of four-wheel-drive electrical vehicle based on lateral tyre-road forces and sideslip angle observer

Abstract

Considering some technical and economic reasons, it is not easy to directly measure the vehicular moving parameters (such as tyre-road forces and vehicle sideslip angle) in electronic stability programme systems. This study proposes a method to estimate lateral tyre-road forces and vehicle sideslip angle by utilising real-time measurements, based on the unscented Kalman filter. Direct-yaw-moment control can effectively guarantee the stability of vehicle while steering at a high speed. This study proposed a hierarchical control strategy as the solution to the problem of the yaw-moment distribution. The overloop controller is designed to calculate the desired yaw moment based on the estimated lateral tyre-road forces and sideslip angle, using the sliding mode control. The servo-loop controller is designed to optimise the torque distribution using weighted-least-squares method based on the desired yaw moment obtained from the overloop controller. MATLAB/Simulink with Carsim is applied for the simulation experiment, the results demonstrate the effectiveness of the lateral tyre-road force and sideslip angle observer, and the optimal allocation controller could improve the handling stability and energy efficiency dramatically.