Patent ID: 7739001
Filing Date: 2010-06-15
Classification: B62D

Abstract:
1. A vehicle steering apparatus for changing a steering angle of a steered wheel of a vehicle in accordance with operation of a steering wheel, the steering apparatus comprising: a steering force assist device including a motor for generating a steering assist force to assist a driver steering input to the steering wheel; a variable transmission ratio device including a motor for steering the steered wheel, the steering angle of the steered wheel being determined by superimposing a first steering angle, based on a turning angle of the steering wheel, and a second steering angle, based on drive of the motor of the variable transmission ratio device, in which the variable transmission ratio device adjusts the second steering angle to change the ratio of the steering angle of the steered wheel relative to the turning angle of the steering wheel; a determination unit for determining a steering characteristic of the vehicle, wherein when the steering characteristic is oversteer, the variable transmission ratio device changes the second steering angle to move the steered wheel to a steering angle in a direction opposite to the present steering angle of the steered wheel with respect to a straight traveling direction of the vehicle; a control unit for controlling the steering force assist device, the control unit including a torque compensation control unit for modifying the assist force applied by the steering force assist device to counteract a returning force generated at the steered wheel due to the change in the second steering angle when the steering characteristic is oversteer, wherein the torque compensation control unit increases the modification of the assist force as the speed at which the second steering angle changes increases.