Steering control system and control method thereof

1. A steering control system comprising:

a control unit configured to perform steering control using a steering torque and a steering angle detected by a steering torque sensor and a steering angle sensor of a vehicle and determine whether the steering torque and/or the steering angle is changed by a disturbance,

wherein the control unit is configured to, when it is determined that a currently detected steering torque and/or steering angle is changed by the disturbance, perform current steering control based on a previously detected steering torque and/or steering angle, which was previously detected by the steering torque and/or the steering angle while there was no disturbance, without using the currently detected steering torque and/or steering angle, which is currently detected by the steering torque and/or the steering angle, for performing the current steering control.

2. The steering control system of claim 1 , wherein when only one of the steering torque and the steering angle is changed, the control unit determines that the change is made by a disturbance.

3. The steering control system of claim 1 , wherein when directions of change of the steering torque and the steering angle are inconsistent with a predetermined reference direction, the control unit determines that the change of the steering torque and the steering angle is made by a disturbance.

4. The steering control system of claim 1 , wherein when a rate of change of the steering angle is not constant, the control unit determines that the change of the steering angle is made by a disturbance.

5. The steering control system of claim 1 , wherein when a number of times it is determined that the change of the steering torque or the steering angle is made by a disturbance exceeds a predetermined reference number, the control unit performs control such that an error notification is output.

6. The steering control system of claim 1 , wherein,

the vehicle has an autonomous driving system, and

the control unit performs control such that steering assistance is provided according to the autonomous driving system when the steering torque and the steering angle are changed such that directions of change of the steering torque and the steering angle are consistent with a predetermined reference direction and a rate of change of the steering angle is constant while a driver does not grip a steering wheel.

7. The steering control system of claim 1 , wherein,

the vehicle has an autonomous driving system, and

when the steering torque and the steering angle are changed such that directions of change of the steering torque and the steering angle are consistent with a predetermined reference direction and a rate of change of the steering angle is constant while a driver grips a steering wheel, the control unit performs control such that steering assistance is provided according to the driver's driving operation when the vehicle is in a non-dangerous area and performs control such that steering assistance is provided according to the autonomous driving system when the vehicle is in a dangerous area.

8. The steering control system of claim 1 , wherein,

the vehicle has an autonomous driving system, and

the control unit is configured to:

ascertain a curved travel road using at least one of sensing data and map data;

extract an alternative lateral acceleration parameter replacing a normal lateral acceleration parameter from the map data when the curved travel road is ascertained; and

generate a target output signal and output the generated target output signal to an actuator so that the steering of the vehicle on the curved travel road is controlled on the basis of the sensing data and the alternative lateral acceleration parameter.

9. The steering control system of claim 1 , wherein,

the vehicle has an autonomous driving system, and

the steering control system further comprises a map data setting device configured to:

predict whether the vehicle deviates from a normal travel route on a travel road by comparing an abnormal lateral acceleration parameter estimated when the state of the vehicle is abnormal to a normal lateral acceleration parameter corresponding to when the state of the vehicle is normal;

predict whether the vehicle deviates from the travel road when it is predicted that the vehicle deviates from the normal travel route and configured to calculate an alternative lateral acceleration parameter replacing the normal lateral acceleration parameter of the travel road when it is predicted that the vehicle deviates from the travel road; and

update prestored map data by applying the alternative lateral acceleration parameter to the map data.

10. The steering control system of claim 1 , further comprising an over-the-air (OTA) controller connected to a controller area network (CAN) gateway of the vehicle and the control unit and configured to perform a software update on the control unit in a wireless manner and bypass CAN data between the control unit and the CAN gateway.

11. The steering control system of claim 1 , further comprising an OTA controller connected to an on-board diagnostics (OBD) module of the vehicle which performs CAN communication with the control unit through a CAN gateway of the vehicle and configured to perform a software update on the control unit in a wireless manner.

12. The steering control system of claim 1 , wherein the control unit is configured to, when it is determined that the currently detected steering torque and/or steering angle is changed by the disturbance, use a latest steering torque and/or steering angle, which was previously detected while there was no disturbance, as the current steering torque and/or steering angle to perform the steering control by maintaining previously performed steering control, which was previously performed by the control unit while there was no disturbance, without using the currently detected steering torque and/or steering angle.

13. A control method of a steering control system, the control method comprising:

detecting a steering torque and a steering angle of a vehicle;

determining whether the steering torque and/or the steering angle is changed by a disturbance; and

when it is determined that a currently detected steering torque and/or steering angle is changed by the disturbance, performing current steering control based on a previously detected steering torque and/or steering angle, which was previously detected by the steering torque and/or the steering angle while there was no disturbance, without using the currently detected steering torque and/or steering angle, which is currently detected by the steering torque and/or the steering angle, for performing the current steering control.

14. The control method of claim 13 , wherein the performing of the steering control comprises:

determining that the change of the steering torque is made by a disturbance when any one of the steering torque and the steering angle is changed and the other is not changed;

determining that the change of the steering torque and the steering angle is made by a disturbance when directions of change of the steering torque and the steering angle are inconsistent with a predetermined reference direction; and

determining that the change of the steering angle is made by a disturbance when a rate of change of the steering angle is not constant.

15. The control method of claim 13 , wherein the performing of the steering control comprises performing control such that an error notification is output when a number of times it is determined that the change of the steering torque or the steering angle is made by a disturbance exceeds a predetermined reference number.

16. The control method of claim 13 , wherein,

the vehicle has an autonomous driving system, and

the performing of the steering control comprises:

performing control such that steering assistance is provided by the autonomous driving system on assumption that the steering torque and the steering angle are changed such that directions of change of the steering torque and the steering angle are consistent with a predetermined reference direction and a rate of change of the steering angle is constant while a driver does not grip a steering wheel; and

performing control such that steering assistance is provided according to a driving operation of the driver when the vehicle is located in a non-dangerous area and performing control such that steering assistance is provided by the autonomous driving system when the vehicle is located in a dangerous area on the assumption that the steering torque and the steering angle are changed such that the directions of change of the steering torque and the steering angle are consistent with the predetermined reference direction and the rate of change of the steering angle is constant while the driver grips the steering wheel.

17. The control method of claim 13 , wherein,

the vehicle has an autonomous driving system, and

the performing of the steering control comprises:

ascertaining a curved travel road using at least one of sensing data and map data;

extracting an alternative lateral acceleration parameter replacing a normal lateral acceleration parameter from the map data when the curved travel road is ascertained; and

generating a target output signal and outputting the generated target output signal to an actuator so that the steering of the vehicle on the curved travel road is controlled on the basis of the sensing data and the alternative lateral acceleration parameter.

18. The control method of claim 13 , wherein,

the vehicle has an autonomous driving system, and

the performing of the steering control further comprises:

predicting whether the vehicle deviates from a normal travel route on a travel road by comparing an abnormal lateral acceleration parameter estimated when the state of the vehicle is abnormal to a normal lateral acceleration parameter corresponding to when the state of the vehicle is normal;

predicting whether the vehicle deviates from the travel road when it is predicted that the vehicle deviates from the normal travel route and calculating an alternative lateral acceleration parameter replacing the normal lateral acceleration parameter of the travel road when it is predicted that the vehicle deviates from the travel road; and

updating prestored map data by applying the alternative lateral acceleration parameter to the map data.