Vehicle steering control device for controlling steering assist torque

Abstract

A steering control device of a vehicle, equipped with power steering system, provides information of a turning limit during an initial phase of understeer condition for a driver, with a temporal reduction of torque for rotating a steering wheel by increasing steering assist torque. If the understeer condition is advanced after the information is generated, steering torque is increased in the direction of turning the vehicle by decreasing the steering assist torque, discouraging the driver from rotating the steering wheel in the turning direction. As an angular speed of rotating the steering wheel increases, steering torque is modulated to be higher, in order to limit the increase of steering angle of steered wheels due to the rotation of the steering wheel as small as possible. At a low vehicle speed, the modification of steering assist torque may not be executed.

Dependencies are inferred from the claim text.