Hydraulic four-wheel steering system
The hydraulic four-wheel steering system consists of oil storage tank, oil pump, rear wheel control valve, throttle position sensor, steering wheel angle sensor, 4WS electronic control unit (ECU), vehicle speed sensor, wheel speed sensor, power cylinder and solenoid valve. .
The hydraulic four-wheel steering system comprehensively judges the running condition of the vehicle at any time, and can precisely control the deflection angle of the rear wheel, thereby improving the steering stability during the high-speed driving of the automobile. The hydraulic oil is input from the oil pump to the solenoid valve and the rear wheel control valve, and then enters the power cylinder capable of controlling the deflection angle of the rear wheel according to the instruction of the 4WS electronic control unit. The 4WS electronic control unit controls the rear wheel deflection angle into two parts: basic control and correction control. The basic controls include stability control and return control.
When the car is driving at a high speed, the steering wheel is rotated slowly, and the rear wheel is deflected in the same direction as the front wheel for stability control; when the car is driving at low and medium speeds, the rear wheel and the front wheel are reversely deflected in the initial stage of turning the steering wheel, and then Gradually back to normal, that is, to return to positive control. The correction control is to correct the amount of the same direction deflection or the reverse deflection of the rear wheel according to the road traffic condition and the operation condition of the driver, so that the rear wheel reaches the desired deflection angle. The maximum deflection angle of the rear wheel of the steering system is small, and the reduction of the minimum steering radius of the vehicle is limited.