Electric four-wheel steering system
The electric front and rear wheel steering system of the electric four-wheel steering system are all electric power. There is no mechanical connection device and hydraulic piping between the two steering gears. The steering of the front and rear wheels is directly controlled. The front and rear wheel steering angles are controlled accurately and freely. High degree, simple mechanism and so on.
The electric four-wheel steering system consists of a microcomputer control unit, front and rear wheel steering actuators, main and auxiliary front wheel steering sensors, main and auxiliary rear wheel steering sensors, rear wheel speed sensors, and vehicle speed sensors. The rear wheel steering actuator includes an electric motor that mechanically drives the steering rack through a recirculating ball screw. The return spring in the actuator pushes the rear wheel to the straight travel position when the ignition switch is turned off or when the four-wheel steering system fails. A rear wheel angle sensor and a secondary rear wheel angle sensor are mounted on the top of the rear wheel steering actuator.
When the engine is running, if the steering wheel is turned, the four-wheel steering control unit receives the information of all the sensors and analyzes them, and determines the deflection angle of the rear wheels through the internal preset control mode. Then controlling the motor in the rear wheel deflection mechanism to drive the spherical raceway nut to rotate, pushing the spherical raceway screw to move, causing the rear wheel to deflect, and the electronic control unit further feedbacks the signal according to the primary and secondary deflection angle sensors in the rear wheel deflection mechanism. The deflection angle of the rear wheel is corrected.