4-WHEEL DRIVE STEERING SYSTEM OF DIRECT YAW MOMENT CONTROL TYPE OF VEHICLE

摘要

PURPOSE: A 4-wheel drive steering system of a direct yaw moment control type of a vehicle is provided to keep a lateral glide angle of the vehicle zero by controlling driving torque of right and left tires actively and to have a steering characteristic similar to a front wheel drive vehicle when turning at high speed. CONSTITUTION: In a 4-wheel drive steering system of a direct yaw moment control type of a vehicle, an ECU(Electronic Control Unit,30) receives a current vehicle speed sensed by a vehicle speed sensor(4), a synchronous steering angle of front wheels(10) and rear wheels(12) sensed by a steering angle sensor(5) and yaw speed of the vehicle sensed from a yaw rate sensor(6), and calculates yaw moment through substitution of the current speed, reference yaw speed of 2WS input previously, detected yaw speed, linear cornering force of front wheel tires, linear cornering force of rear wheel tires, a distance from the gravity center of the vehicle to the front wheels, and a distance from the gravity center of the vehicle to the rear wheels. The ECU controls an actuator(34) for driving brake devices(32) mounted to front wheels according to the calculated and output yaw moment value, instantaneously brakes the front wheels, and releases the braking of the front wheels by intercepting an operation signal of the actuator.