Patent ID: 7540351

Claim:
A steering control system for a vehicle with a plurality of wheels, the steering control system comprising: a steering wheel; a steering shaft including an upper shaft portion and a lower shaft portion, wherein torque is transmitted to the upper shaft portion by a steering input to the steering wheel, wherein steering shaft torque of the lower shaft portion corresponds to the torque transmitted to the upper shaft portion, and wherein the steering shaft torque steers the wheels; a steering torque detector which generates an output signal corresponding to a torsion angle between the upper shaft portion and the lower shaft portion to detect a steering torque; an assist force generating device that generates an assist force according to a control signal to thereby generate torque in the lower shaft portion; a controller for outputting the control signal to the assist force generating device based upon the steering torque detected by the steering torque detector; a vehicle speed detector that detects a speed of the vehicle; and an environment information detector that detects environment information of the vehicle, the environment information including an environment of a road ahead of the vehicle on which the vehicle is traveling, wherein the controller comprises: a basic assist amount setting device that sets a basic assist amount according to the vehicle speed detected by the vehicle speed detector and to the steering torque detected by the steering torque detector; a torque correction amount setting device that determines a torque correction amount based upon the environment information detected by the environment information detector; and an assist correction device that determines the assist force based upon the basic assist amount set by the basic assist amount selling device and the torque correction amount determined by the torque correction amount setting device.