System and method for predicting a possible lane departure when driving a vehicle autonomously or semi-autonomously, and for taking a remedial action to prevent a lane departure

1. A system comprising:

a lane boundary circuit configured to determine a boundary of a lane within which a vehicle is travelling;

a vehicle trajectory circuit configured to predict a trajectory of the vehicle;

an intersection location circuit configured to determine M locations of M intersections between the vehicle trajectory and the lane boundary at M times, wherein M is an integer greater than one;

a lane departure circuit configured to:

determine a distance between two of the M locations that are consecutively determined; and

identify a potential lane departure based on the distance; and

a driver warning circuit configured to activate a driver warning device to warn a driver when the potential lane departure is identified.

2. The system of claim 1 wherein the lane departure circuit is configured to:

determine N distances between N pairs of the M locations that are consecutively determined; and

identify the potential lane departure based on the N distances, wherein N is an integer greater than one.

3. The system of claim 2 wherein the lane departure circuit is configured to identify the potential lane departure when at least P of the N distances are less than a threshold, and P is an integer greater than one.

4. The system of claim 3 further comprising a steering control circuit configured to control a steering actuator to steer the vehicle independent of a driver input, wherein the threshold indicates a variability of Q distances between an actual path of the vehicle and a desired path of the vehicle when the vehicle is maintained within the lane boundary while being steered independent of the driver input, and Q is an integer greater than one.

5. The system of claim 3 wherein the lane departure circuit is configured to adjust at least one of the threshold and P based on a radius of the lane boundary.

6. The system of claim 1 wherein:

the intersection location circuit is configured to identify each of the M locations using an X coordinate and a Y coordinate;

the X coordinate indicates a location along a length of a road on which the vehicle is travelling; and

the Y coordinate indicates a location along a width of the road on which the vehicle is travelling.

7. The system of claim 1 wherein the lane boundary circuit is configured to determine the lane boundary based on an input from a forward facing camera mounted on the vehicle, a side facing camera mounted on the vehicle, and a global positioning system.

8. The system of claim 1 wherein the vehicle trajectory circuit is configured to predict the vehicle trajectory based on at least one of a wheel speed, vehicle acceleration, a steering wheel angle, and an input from a global positioning system.

9. The system of claim 1 further comprising at least one of:

a powertrain control circuit configured to control a powertrain of the vehicle to decelerate the vehicle when the potential lane departure is identified; and

a brake control circuit configured to control a friction brake of the vehicle to decelerate the vehicle when the potential lane departure is identified.

10. A method comprising:

determining a boundary of a lane within which a vehicle is travelling;

predicting a trajectory of the vehicle;

determining M locations of M intersections between the vehicle trajectory and the lane boundary at M times, wherein M is an integer greater than one;

determining a distance between two of the M locations that are consecutively determined; and

identifying a potential lane departure based on the distance; and

activating a driver warning device to warn a driver when the potential lane departure is identified.

11. The method of claim 10 further comprising:

determining N distances between N pairs of the M locations that are consecutively determined; and

identifying the potential lane departure based on the N distances, wherein N is an integer greater than one.

12. The method of claim 11 further comprising identifying the potential lane departure when at least P of the N distances are less than a threshold, and P is an integer greater than one.

13. The method of claim 12 further comprising controlling a steering actuator to steer the vehicle independent of a driver input, wherein the threshold indicates a variability of Q distances between an actual path of the vehicle and a desired path of the vehicle when the vehicle is maintained within the lane boundary while being steered independent of the driver input, and Q is an integer greater than one.

14. The method of claim 12 further comprising adjusting at least one of the threshold and P based on a radius of the lane boundary.

15. The method of claim 10 further comprising identifying each of the M locations using an X coordinate and a Y coordinate, wherein:

the X coordinate indicates a location along a length of a road on which the vehicle is travelling; and

the Y coordinate indicates a location along a width of the road on which the vehicle is travelling.

16. The method of claim 10 further comprising determining the lane boundary based on an input from a forward facing camera mounted on the vehicle, a side facing camera mounted on the vehicle, and a global positioning system.

17. The method of claim 10 further comprising predicting the vehicle trajectory based on at least one of a wheel speed, vehicle acceleration, a steering wheel angle, and an input from a global positioning system.

18. The method of claim 10 further comprising at least one of:

controlling a powertrain of the vehicle to decelerate the vehicle when the potential lane departure is identified; and

controlling a friction brake of the vehicle to decelerate the vehicle when the potential lane departure is identified.