Cross-coupling active current balance fast terminal sliding mode control for dual-winding steer-by-wire system

The dual-winding steer-by-wire (DW-SBW) system is a novel steer-by-wire system with dual-winding permanent magnet synchronous motors, which improves steering capability and safety. However, the current imbalance in two stator windings may lead to increased current harmonic and torque ripple, resulting in steering performance degradation and safety jeopardization. Therefore, in order to improve the current balancing capability of the DW-SBW system, this paper proposes a cross-coupling active current balance control strategy. The dynamic model and the current imbalance model of the DW-SBW system are established. The mathematical relationship between the winding parameters asymmetry and current imbalance is derived, and the impact of current imbalance on current harmonic and steering performance is revealed. A radial basis function (RBF) based active current balance fast terminal sliding mode control (FTSMC) strategy for a DW-SBW system is proposed. The fast terminal sliding mode control is applied to cross-compensate the q-axis current loop control output of the two stator windings, while the RBF neural network is used to estimate the asymmetry of the resistance and inductance parameters of the two windings. The performance of the proposed FTSMC-RBF controller is validated through computer simulations and dual-winding motor experiments. The results demonstrate that the proposed FTSMC-RBF controller is more robust and provides better current balancing performance than the FTSMC in the presence of model parameter uncertainties.