Steering Angle Control of SBW System Based on Internal Model Control

The steering angle control is significant for the lateral motion control in the trajectory tracking control of autonomous vehicle. This research proposed a steering tracking control method of the steering-by-wire system based on Internal Model Control (IMC) to solve the uncertainty of steering system model and aligning torque on tracking control. This paper simplified the steer-by-wire system, and established the torque equation to identify the parameters of the steering system. Based on the principle of the Expanded State Observer (ESO) in the Active Disturbance Rejection Control (ADRC), from the perspective of the steering system model, the aligning torque is regarded as the external disturbance of the system, and the disturbance is dynamically estimated in real time. Based on the IMC theory, an angle tracking controller combining an ideal controller and a second-order low-pass filter is designed for the steer-by-wire system. Finally, the simulation test proved that the designed estimator of the aligning torque can accurately obtain the aligning torque value in real time. The designed internal model controller can track the desired angle quickly and accurately, and it has good robustness against model mismatch and external disturbance.