Lane-centering assistance

1. A vehicle control system comprising a computer comprising a processor and a memory storing instructions executable by the processor to:

in response to detecting hands being off a steering wheel of a vehicle for a threshold time while a lane-centering assist operation is active, steer the vehicle along a generated path from a center of a lane to a lateral position between the center of the lane and an edge of the lane;

then steer the vehicle from the lateral position to the center of the lane; and

then maintain the vehicle at the center of the lane;

wherein, from a time of detecting the hands being off the steering wheel to a time of maintaining the vehicle at the center of the lane, steering the vehicle away from the center of the lane occurs a single time; and

the path is represented by a polynomial function of a lookahead distance.

2. The vehicle control system of claim 1 , wherein steering the vehicle from the center of the lane to the lateral position includes generating the path along which a control module guides the vehicle.

3. The vehicle control system of claim 2 , wherein generating the path includes generating a plurality of paths to a series of intermediate lateral positions between the center of the lane and the lateral position.

4. The vehicle control system of claim 1 , wherein the instructions further include to, while steering the vehicle from the center of the lane to the lateral position, refrain from outputting a warning to an occupant of the vehicle.

5. The vehicle control system of claim 1 , wherein the instructions further include to, while steering the vehicle from the lateral position to the center of the lane, refrain from outputting a warning to an occupant of the vehicle.

6. The vehicle control system of claim 1 , wherein the instructions further include to, while maintaining the vehicle at the center of the lane after steering the vehicle from the lateral position, output a warning to an occupant of the vehicle.

7. The vehicle control system of claim 1 , wherein the instructions further include to, in response to a hand on the steering wheel while steering the vehicle from the center of the lane to the lateral position, steer the vehicle to the center of the lane without reaching the lateral position.

8. The vehicle control system of claim 1 , wherein the instructions further include to determine the lateral position before steering the vehicle from the center of the lane to the lateral position.

9. A method comprising:

in response to detecting hands being off a steering wheel of a vehicle for a threshold time while a lane-centering assist operation is active, steering the vehicle along a generated path from a center of a lane to a lateral position between the center of the lane and an edge of the lane;

then steering the vehicle from the lateral position to the center of the lane; and

then maintaining the vehicle at the center of the lane;

wherein, from a time of detecting the hands being off the steering wheel to a time of maintaining the vehicle at the center of the lane, steering the vehicle away from the center of the lane occurs a single time; and

the path is represented by a polynomial function of a lookahead distance.

10. The method of claim 9 , wherein steering the vehicle from the center of the lane to the lateral position includes generating the path along which a control module guides the vehicle.

11. The method of claim 10 , wherein generating the path includes generating a plurality of paths to a series of intermediate lateral positions between the center of the lane and the lateral position.

12. The method of claim 9 , further comprising, while steering the vehicle from the center of the lane to the lateral position, refraining from outputting a warning to an occupant of the vehicle.

13. The method of claim 9 , further comprising, while steering the vehicle from the lateral position to the center of the lane, refraining from outputting a warning to an occupant of the vehicle.

14. The method of claim 9 , further comprising, while maintaining the vehicle at the center of the lane after steering the vehicle from the lateral position, outputting a warning to an occupant of the vehicle.

15. The method of claim 9 , further comprising, in response to a hand on the steering wheel while steering the vehicle from the center of the lane to the lateral position, steering the vehicle to the center of the lane without reaching the lateral position.

16. A vehicle control system comprising:

means for detecting whether hands of an occupant are on a steering wheel of a vehicle;

means for steering the vehicle to a lateral position in a lane; and

a computer programmed to,

in response to detecting hands being off the steering wheel for a threshold time while a lane-centering assist operation is active, steer the vehicle along a generated path from a center of the lane to the lateral position;

then steer the vehicle from the lateral position to the center of the lane; and

then maintain the vehicle at the center of the lane;

wherein, from a time of detecting the hands being off the steering wheel to a time of maintaining the vehicle at the center of the lane, steering the vehicle away from the center of the lane occurs a single time; and

the path is represented by a polynomial function of a lookahead distance.