Yaw stability control for steer-by-wire vehicle based on radial basis network and terminal sliding mode theory

To further improve the handling and steering performance of steer-by-wire vehicles, a layered control strategy is proposed for the steer-by-wire system, which includes the upper and lower controllers. In the upper control, considering the vehicle sideslip angle and yaw rate, an adaptive sliding mode control strategy is designed for the vehicle lateral stability. Due to the measurement difficulty of the sideslip angle, a robust sliding mode observer is designed to estimate the sideslip angle. In the lower control, a new adaptive global fast terminal sliding mode is proposed to ensure the tracking accuracy of the front wheel angle, considering the dynamic uncertainty characteristics of the steering-by-wire system. The adaptive part of the lower control adopts a radial basis function network, and the adaptive law is designed in Lyapunov sense to make the network approximate the unknown dynamics of the steering-by-wire system, thus the parameters of the steering-by-wire are not required to be completely known. Finally, the joint simulation of MATLAB/Simulink and Carsim verifies that the proposed layered controller has excellent control performance.