Harmonic suppression and road feeling control of steer-by-wire system with permanent magnet synchronous motor

In this paper, a hierarchical control strategy is proposed to improve the quality of road feeling control of a steer-by-wire system. The upper layer proposed a road feeling torque control method of uncertain system, and the lower layer suppresses the current harmonics produced in the road feeling control process. Firstly, the dynamic model of the steer-by-wire system and the vehicle are established. Secondly, considering the influence of uncertain system parameters, uncertain harmonic torque ripple, and uncertain sensor noise on the road feeling torque control, a road feeling torque control strategy based on mixed H2/H∞ robust control theory is designed. Then, a current harmonic suppression strategy based on the extended Kalman filter is proposed in the lower layer to suppress the current harmonics of all frequencies. Finally, the simulation is conducted using MATLAB/Simulink, and the experimental verification is carried out on the steer-by-wire experimental platform. Simulation and experimental results show that the proposed road feeling control strategy is robust to nonlinear system uncertainties, and the proposed current harmonic suppression strategy can suppress current harmonics in all frequency ranges.