Steering apparatus for vehicle and control method therefor

1 . A method for controlling a vehicle including a steering-by-wire (SBW) system, the method comprising:

calculating a maximum limit steering value of a steering wheel of the vehicle in response to an occurrence of an abnormality at the SBW system;

calculating a correction coefficient for the maximum limit steering value based on a speed of the vehicle and a road surface condition;

generating an endpoint reaction force impression for the steering wheel;

determining whether a required steering value input to the steering wheel exceeds the maximum limit steering value; and

outputting a warning sound and applying the endpoint reaction force to the steering wheel in response to determining that the required steering value exceeds the maximum limit steering value.

2 . The method of claim 1 , wherein calculating the maximum limit steering value of the steering wheel includes calculating a lateral acceleration of the vehicle based on a rotation compensation value due to one-way braking of the vehicle, a rotation compensation value due to a driving force of the vehicle, and a steering angle by a rear wheel steering system of the vehicle.

3 . The method of claim 2 , wherein calculating the maximum limit steering value of the steering wheel includes:

estimating a rotation radius of the vehicle by calculating the speed of the vehicle and the lateral acceleration of the vehicle; and

determining a maximum limit steering value based on the estimated rotation radius and a wheelbase value of the vehicle.

4 . The method of claim 1 , wherein the correction coefficient is set to correct the maximum limit steering value based on a road surface friction coefficient.

5 . The method of claim 1 , wherein outputting the warning sound and applying the endpoint reaction force to the steering wheel include applying an endpoint steering impression to the steering wheel by setting a resistance value based on a steering angle of the steering wheel.

6 . An apparatus for controlling a vehicle including a steering-by-wire (SBW) system, the apparatus comprising:

a sensor unit configured to detect driving information of the vehicle;

a main controller configured to implement backup steering using rear wheels of the vehicle in response to an occurrence of an abnormality in the SBW system, the backup steering including the main controller configured to determine a maximum limit steering value of the vehicle;

a steering wheel configured to receive a required steering value based on a driver's steering intention; and

a reaction force generation actuator configured to generate a backup steering reaction force impression for the steering wheel based on the maximum limit steering value.

7 . The apparatus of claim 6 , wherein the sensor unit is configured to detect at least one of a speed of the vehicle, a driving direction of the vehicle, an angular velocity of the vehicle, and a road surface condition.

8 . An apparatus for controlling a vehicle including a steering-by-wire (SBW) system, the apparatus comprising:

a sensor unit configured to detect driving information of the vehicle;

a main controller configured to generate a backup steering reaction force impression for the SBW system and determine a maximum limit steering value of the vehicle;

a steering wheel configured to receive a required steering value based on a driver's steering intention; and

a reaction force generation actuator configured to generate a reaction force impression for the steering wheel based on the maximum limit steering value;

wherein the main controller is configured to calculate:

a lateral acceleration of the vehicle based on a rotation compensation value due to one-way braking of the vehicle;

a rotation compensation value due to a driving force of the vehicle; and

a steering angle by a rear wheel steering system of the vehicle.

9 . The apparatus of claim 8 , wherein the main controller is further configured to:

estimate a rotation radius of the vehicle by calculating a speed of the vehicle and the lateral acceleration of the vehicle;

determine a maximum limit steering value based on the estimated rotation radius and a wheelbase value of the vehicle; and

calculate, based on a road surface condition, a correction coefficient for the maximum limit steering value.

10 . The apparatus of claim 6 , wherein the main controller is configured to:

determine whether the required steering value received by the steering wheel exceeds the maximum limit steering value; and

output a warning sound and apply a vibration to the steering wheel in response to determining that the required steering value exceeds the maximum limit steering value.