Design and applications of steering angle tracking control with robust compensator for steer-by-wire system of intelligent vehicle

The steer-by-wire (SBW) system is a key component for an intelligent vehicle, which is related to the safety, comfort, and drivability of vehicle. Hence, it is supposed to ensure strong robustness and functional safety under various operating conditions, which is one of the main difficulties of SBW. In this paper, a linear quadratic regulator (LQR) with a novel robust compensator is designed for steering angle control of SBW to improve the tracking performance. The SBW actuator is regarded as a permanent magnet synchronous motor (PMSM) control system with parameter perturbation and external disturbance, including Coulomb friction and self-aligning torque. Theoretical analysis proves that the proposed method can ensure the system stability and make the tracking error converge to zero against multiple uncertainties. The main parameters are obtained by offline calculation and the online calculation burden is small, so the proposed method is suitable for vehicle applications. Both simulations and experiments show that the robust compensator is effective.