Provided is a four-wheel steering system capable of providing better maneuverability with a small turning radius. The four-wheel steering system includes a front-wheel steering system that steers front wheels of a vehicle and a rear-wheel steering system that steers rear wheels of the vehicle in accordance with a steering angle of a steering wheel. When the vehicle speed is lower than a vehicle speed threshold, the rear-wheel steering system steers the rear wheels in an opposite direction to that in which the front wheels are steered. When the vehicle speed is lower than the vehicle speed threshold, the rear-wheel steering system sharply increases the rate of increase in target steered angle (θ*) of the rear wheels with respect to an increase in steering angle (θ) when an absolute value of the steering angle (θ) is equal to or larger than an absolute value of an angle threshold (θ, -θ). The front-wheel steering system has a motor that is a source of a steering assist force and a first ECU that controls the motor in accordance with the steering state. When the vehicle speed is lower than the vehicle speed threshold, the first ECU controls the motor so as to sharply increase the rate of increase in steering torque (T) with respect to an increase in steering angle (θ) when the absolute value of the steering angle (θ) is equal to or larger than the absolute value of the angle threshold (θ, -θ).
FOUR-WHEEL STEERING SYSTEM
VIERRADLENKUNG
SYSTÈME DE DIRECTION À QUATRE ROUES
2021-05-26
Patent
Electronic Resource
English
IPC: | B62D MOTOR VEHICLES , Motorfahrzeuge |