A linear vehicle model is commonly employed in the controller design for an active front steering (AFS). However, this simplified model has a considerable influence on the accuracy of the controller. In this article, an AFS controller using an active disturbance rejection control (ADRC) technique is proposed to prevent this problem. The AFS controller was established in MATLAB/Simulink to control the CarSim vehicle model for verification of the simulation. Under the straight-line driving disturbance condition, proportion-integration-differentiation (PID) control and ARDC substantially decreased with respect to the uncontrolled lateral offset and ADRC performed better than PID control. Under the double lane change (DLC) test working condition, the tracking error of the path, yaw rate, roll angle, and lateral acceleration, and error of the driving direction were used to evaluate the vehicle’s controllability and stability. These evaluation indexes were substantially improved by PID control and ADRC; similarly, ADRC was better than PID control. The tracking error of the ADRC in the presence of parameter variance and external disturbance was significantly smaller than that of PID control. The results have verified that the AFS controller based on ADRC can significantly improve vehicle controllability and stability.
Active disturbance rejection control for fractional-order PID control system research
