Study On Control Of The Steering Electromotor Of SBW

Steer-by-Wire System (SBW) is a new steering system which instead the mechanical transmission and conjunction with wire and controllers between the driver's steering behavior and the wheels of the vehicle. The intelligent mechanical and electric transferring equipments is the core technique of control of SBW. The equipments change the electronic signs of the driver's steering commands into mechanical actions and feedback dynamical information to the driver still by the electronic signs. So SBW achieves the intelligent steering control.The steering electromotor is the power source of SBW. It provides the steering torque for the vehicle. Based on the characteristic of the steering electromotor, we can control the voltage or current of the armature so as to control the torque of the steering electromotor.This article researches the composing and work principle of SBW, based on which, we select brush-direct-current-motor as the steering electromotor of SBW and study its drive and control mode and select limited monopole PWM as the drive mode of the steering electromotor. It is easy to achieve and it can ensure upper precision of control. By researching on the model of SBW, we establish the dynamics model of the steering electromotor and mostly study the control strategy of the torque of the steering electromotor, which emphasizes the voltage and the current PID closed loop control of the electromotor. The results of the simulation indicate that the current PID closed loop control of the electromotor can achieve that the current of the steering electromotor trail after the target current exactly, which satisfies the control requests of the steering electromotor. At last, we establish the model of the target current conformed by the angle of the steering wheel and simulate the model of SBW, which adopts the current PID closed loop control of the electromotor. By comparing its response of the yaw rate and the excursion rate of the center of the mass of the vehicle with the vehicle equipped with mechanical steering system, we validate the model and prove the current PID closed loop control strategy of the steering electromotor is feasible.