This paper briefly introduces the vehicle characteristics of four-wheel steering.
Based on the parameters of an electric SUV, a linear two-degree-of-freedom
vehicle dynamics model is established, and the transfer function of the rear
wheel steering angle is derived to keep the sideslip angle at the center of
gravity(CoG) constant at zero and proportional to the front wheel steering angle
under steady state. The active rear wheel steering control strategy based on
zero sideslip angle is established by MATLAB/Simulink, and a co-simulation model
is built with CarSim and the HIL test bench to simulate and analyze the proposed
control strategy.
Subsequently, through classic handling stability test conditions such as the
snake test, steering angle step test, and double lane change test, the influence
of active rear wheel steering on vehicle dynamic response indicators such as
sideslip angle, lateral acceleration, and yaw rate is studied, and the control
effect is compared with that of the feedforward control rear wheel steering
strategy. Test results demonstrate that the rear-wheel steering technology based
on zero sideslip angle control improves the vehicle's low-speed maneuverability
and high-speed stability. Under the double lane change test condition at 80
km/h, the sideslip angle is reduced by approximately 30%, and the yaw rate gain
is decreased by about 25% compared to the feedforward control strategy. These
enhancements significantly improve the overall dynamic performance of the
vehicle.