Patent ID: 7664584

Claim:
A steering apparatus comprising: a steering wheel; turning wheels that are selectively turned according to a steering angle of the steering wheel; a backup mechanism including a clutch for alternately mechanically separating and linking the steering wheel and the turning wheels; a turning actuator, linked to the turning wheels, that turns the turning wheels according to the steering angle of the steering wheel; a steering reaction force actuator, linked to the steering wheel, for assigning a reaction torque to the steering wheel according to a turning torque assigned to the turning wheels by the turning actuator; and a control unit configured to control the backup mechanism, the steering reaction force actuator, and the turning actuator, wherein the control unit includes: a steer-by wire control configured to, when the steering wheel and the turning wheels are mechanically separated from each other by the backup mechanism so that the turning wheels are turned by the turning actuator according to the steering angle, assign the reaction torque to the steering wheel; a steering assistance control configured to, when the steering wheel and the turning wheels are mechanically linked by the backup mechanism so that a steering torque inputted from the steering wheel is transferred to the turning wheels via the backup mechanism, assign an assistance force to at least one of the steering reaction force actuator and the turning actuator so as to assist turning of the turning wheels according to the steering torque inputted from the steering wheel; a switching control configured to generate a shift command instructing the clutch to one of mechanically separate and link the steering wheel and the turning wheels for alternately switching between the steer-by wire control and the steering assistance control when a predetermined condition is met; and a correction control configured to correct the turning torque assigned to the turning wheels by the turning actuator in response to the shift command by at least one of: reducing the turning torque provided by the turning actuator after the shift command instructs the clutch to shift from the steer-by wire control to the steering assistance control and before the clutch mechanically links the steering wheel and the turning wheels; and increasing the turning torque provided by the turning actuator after the shift command instructs the clutch to shift from the steering assistance control to the steer-by wire control and before the clutch mechanically separates the steering wheel and the turning wheels.