Research on the Control Strategy of Assisted Motor of Electro-Hydraulic Coupled Steering System for Intelligent Commercial Vehicles Under Emergency Steering Conditions

The commercial vehicle electro-hydraulic coupling steering (EHCS) system in the vehicle encountered emergency conditions for emergency steering, due to the steering system in the assisted motor there is a limitation on the rated speed of the assisted motor, the assisted motor cannot meet the emergency steering on the speed requirements of the motor, so when the driver for emergency steering there will be a problem of heavy feel. In this paper, based on the traditional EHCS, the assisted motor control system is optimally designed and improved. Firstly, the leading angle flux magnetic weakening control strategy is adopted to expand the speed range of the assisted motor. The motor is controlled by constant torque at low speeds and weak magnetic control at high speeds. Then, the active disturbance rejection controller (ADRC) is designed to replace the traditional pure integral PI controller, which improves the dynamic and static characteristics of the speed loop and enhances the system's anti-interference capability. Finally, the control strategy proposed in this paper is simulated and verified by MATLAB/Simulink. The simulation results suggest that the proposed algorithm and controller contribute to effectively improving the control accuracy and robustness of the EHCS, the driving experience and comfort, and enhancing driving safety during emergency steering.