Barrier Lyapunov-based fractional-order sliding-mode direct yaw-moment constrained control design for four-wheel-independent-drive EVs

Abstract

A barrier Lyapunov function based fractional-order sliding mode constraints control method is proposed for four-wheel-independent-drive electrical vehicles (4WID-EVs) in steering condition. The desired side slip angle and yaw rate were obtained by the two degree-of-freedom vehicle dynamic model. After that, a direct yaw-moment algorithm is used to create the ideal yaw-moment by the seven degree-of-freedom models. Then, based on the model above, a fractional-order sliding mode control method is implemented in the upper controller design to address the problem of vehicle instability in critical cases. To meet the vehicle maneuver stability and the transformation error caused by the new prescribed performance control scheme, which is constructed by using the barrier Lyapunov function. To counteract the lumped disturbance, a fixed-time extended state observer is proposed to further enhance the anti-disturbance performance of the designed controller. Finally, a 4WID-EV hardware-in-the-loop platform is constructed for verification. The results demonstrate that the proposed control method outperforms other control methods, with a faster yaw rate stabilization and reduced sideslip, as well as its better anti-disturbance robustness.