Patent ID: 7970513
Filing Date: 2011-06-28
Classification: B62D

Abstract:
1. A steering control apparatus for a vehicle having a steering wheel for steering a pair of right and left steered wheels of said vehicle, a power source for generating power, drive shafts for transferring the power to said right and left steered wheels, to be served as right and left driving wheels of said vehicle, respectively, a characteristic of said drive shafts including at least one of a length and arrangement of said drive shafts being provided asymmetrically with respect to a transverse direction of said vehicle, and traction control means for controlling braking torque applied to said right and left steered wheels, respectively, comprising: braking torque detection means for detecting the braking torque applied to said right and left steered wheels, respectively; driving force difference calculation means for calculating a driving force difference between said right and left steered wheels, on the basis of the braking torque applied to each of said right and left steered wheels detected by said braking torque detection means; power source state detection means for detecting an actuating state of said power source; steering torque control means for controlling steering torque created by said steering wheel, and applying torque steer reducing torque to said steering wheel, to reduce a torque steer for varying a steer-holding force in response to variation of the driving force, the torque steer being caused to vary the steer-holding force resulting from the traction control, and the torque steer being caused to vary the steer-holding force resulting from the characteristic of the drive shafts created in only one direction with respect to the steering direction of the steering wheel; and desired value determination means for determining a desired value of the torque steer reducing torque, on the basis of the driving force difference calculated by said driving force difference calculation means, and the actuating state of said power source detected by said power source state detection means, wherein said steering torque control means applies the torque steer reducing torque to said steering wheel, in accordance with the desired value of the torque steer reducing torque determined by said desired value determination means, to reduce the torque steer; wherein said desired value determination means determines the desired value of the torque steer reducing torque to decrease the torque steer resulting from the traction control and increased according to the characteristic of the drive shafts, in accordance with a first characteristic for determining the desired value, when a sign of the driving force difference is positive, and when the steered direction of the torque steer resulting from the traction control is the same as the steered direction of the torque steer resulting from the characteristic of the drive shafts created in only one direction with respect to the steering direction of the steering wheel, and determines the desired value of the torque steer reducing torque in accordance with a second characteristic for determining the desired value to decrease the torque steer resulting from the traction control and cancelled according to the characteristic of the drive shafts, when the sign of the driving force difference is negative, and when the steered direction of the torque steer resulting from the traction control is opposite to the steered direction of the torque steer resulting from the characteristic of the drive shafts created in only one direction with respect to the steering direction of the steering wheel, said second characteristic being set to provide the desired value of relatively small absolute value compared with said first characteristic.