Due to the presence of uncertain disturbances in the actual steering system,
disturbances in the system may affect the handling stability of the vehicle.
Therefore, this article proposes an integrated steering system control strategy
with stronger anti-disturbance performance. When disturbances exist in the
system, the proposed control strategy effectively reduces the attitude changes
during the vehicle steering process. In the upper-level control strategy, a
variable transmission ratio curve is designed to coordinate the high-speed
handling stability and low-speed steering sensitivity of the vehicle. On this
basis, a sideslip angle observer is proposed based on the extended state
observation theory, which does not depend on an accurate system model, thus
determining the intervention timing of the active front wheel steering system.
In the lower-level control strategy, DR-PI/DR-PID controllers are designed for
the integrated steering system. Finally, experiments are conducted in the
CarSim/Simulink joint simulation environment. The results indicate that compared
to traditional PI/PID controllers and advanced ADRC controllers, DR-PI/DR-PID
controllers can effectively suppress step disturbances, sinusoidal disturbances,
and white noise disturbances while ensuring the dynamic response characteristics
of the system. Under double-lane conditions, the root mean square values of the
yaw rate and sideslip angle decrease by 4.35% to 12.3% and 3.21% to 7.72%,
respectively. Therefore, the designed control strategy can improve handling
stability while ensuring the robustness of the system.
