Influence Factors of Active Steering Control of Independent Wheel Set Based on Hub Motor and Speed Difference Feedback

The active steering control can effectively improve the steering ability of independent wheels. Based on the research of torque ripple of the permanent magnet synchronous motor(PMSM), the source of torque ripple of PMSM is analyzed, and the torque ripple error of hub motor is calculated. The simulation model for active steering control of independently rotating wheel in in-wheel motor is established. The effect of torque ripple on active steering control of independently rotating wheel in in-wheel motor is investigated. Through theoretical derivation and model simulation, when the vehicle runs at a constant speed in a straight line, there is a functional relationship between the control accuracy of the hub motor system and the maximum lateral displacement of the wheelset. When the control accuracy of the hub motor becomes worse, the fluctuation amount of the lateral displacement of the wheel pair also becomes larger. Among them, the equivalent conicity of the wheel tread and the wheel's nominal rolling radius are important influencing factors. The relations between the accuracy of active steering control of independently rotating wheel in in-wheel motor and wheel/rail profile are derived. The method which used to improve the active steering control of independently rotating wheel by optimizing the tread is proposed.