Electric Hydraulic Power Steering System Simulation Study
Properly controlling electro hydraulic power steering system can improve steering performance. The relation of motor speed, vehicle speed and steering speed is gained, according to the influence of motor speed on the steering performance. The force and angle input is set in the driver input model. Rotary valve is simulated by four orifices. The steering resistance between tire and ground is simulated by the coulomb friction on two tips of the rack. The method of double closed-loops PID is used to control the motor. The influence of the control strategy on the steering performance is realized by the simulations of three typical situation, which includes steering portability, road feel, the speed of assist force response and its stability. The results of simulation validate the availability of the control strategy, which is the basic of optimization.