PATH PLANNING FOR EVASIVE STEERING MANEUVER IN PRESENCE OF TARGET VEHICLE AND SURROUNDING OBJECTS

• US 20150120137A1
• Filed: 10/28/2013
• Published: 04/30/2015
• Est. Priority Date: 10/28/2013
• Status: Active Grant

• Current Assignee: GM Global Technology Operations LLC (General Motors Company)
• Original Assignee: GM Global Technology Operations LLC (General Motors Company)
• Inventors: Zeng, Shuqing, Moshchuk, Nikolai K., Jafari, Rouhollah
• Granted Patent: US 9,174,672 B2
• Time in Patent Office: Days
• US Class Current: 701/41
• CPC Class Codes: B60R 21/0134 responsive to imminent contact with an obstacle , e.g. using radar systems
• CPC Class Codes: B60W 10/20 including control of steering systems
• CPC Class Codes: B60W 2420/408 Radar; Laser, e.g. lidar
• CPC Class Codes: B60W 30/09 Taking automatic action to avoid collision, e.g. braking and steering
• CPC Class Codes: B60W 30/095 Predicting travel path or likelihood of collision
• CPC Class Codes: B62D 15/0265 Automatic obstacle avoidance by steering
• CPC Class Codes: B62D 6/00 Arrangements for automatically controlling steering depending on driving conditions sensed and responded to, e.g. control circuits means for initiating a change in direction B62D1/00; steering valves B62D5/06; combined with means for inclining the vehicle body or wheels on bends B62D9/00
• CPC Class Codes: G01S 13/931 of land vehicles
• CPC Class Codes: G01S 2013/9318 Controlling the steering
• CPC Class Codes: G01S 2013/932 using own vehicle data, e.g. ground speed, steering wheel direction
• CPC Class Codes: G05D 1/02 Control of position or course in two dimensions
• CPC Class Codes: G05D 1/024 in combination with a laser lasers per se H01S

Abstract

A method for calculating a virtual target path around a target object that includes providing scan points identifying detected objects and separating the scan points into target object scan points and other object scan points. The method identifies a closest scan point from the target object scan points and identifies a path point that is a predetermined safe distance from the closest scan point. The method determines a straight target line adjacent to the target object that goes through the path point, and determines a distance between the target line and each of the other objects and determines whether all of the distances are greater than a predetermined threshold distance. The method identifies curve points for each other object whose distance is less than the predetermined threshold distance, and identifies a curve path that connects the curve points to be the virtual target path using a quadratic polynomial function.

Claims

1. A method for determining a virtual target path that is used to calculate an evasive steering path for a subject vehicle around a target object in a travel path of the subject vehicle, said method comprising:

providing a plurality of scan points identifying detected objects from one or more sensors on the subject vehicle;

separating the plurality of scan points into target object scan points received from the target object and other object scan points received from other objects if they exist;

identifying a closest scan point from the target object scan points that is the scan point that is the closest to the subject vehicle;

identifying a path point that is a predetermined safe distance from the closest scan point;

determining a straight target line adjacent to the target object that goes through the path point and is parallel to a direction of the travel path of the subject vehicle before the subject vehicle follows the evasive steering path;

determining whether the plurality of scan points include the other object scan points;

making the evasive steering path the straight target line if no other object scan points exist;

determining a distance between the target line and each of the other objects identified by the other object scan points if other object scan points do exist;

determining whether all of the distances are greater than a predetermined threshold distance;

making the evasive steering path the straight target line if all of the distances are greater than the threshold distance;

identifying curve points for each other object whose distance is less than the predetermined threshold distance, where each curve point is a predetermined safe distance from the target object and the other object; and

identifying a curved path that connects the curve points to be the virtual target path.

2. The method according to claim 1 further comprising determining whether the virtual target path is to a left side or a right side of the target object prior to identifying the closest scan point.

3. The method according to claim 2 wherein identifying whether the evasive steering path is to the left side or the right side of the target object includes using the plurality of scan points includes representing a space between the scan points by triangles using Delaunay triangulation, defining vertices at mid-points of edges of the Delaunay triangles, defining segments as lines that connect to vertices and using Dijkstra'"'"'s algorithm to determine a shortest path between a start node and an end node, where the start node is a vertex with a minimum X-coordinate value and the end node is a vertex with a maximum X-coordinate value, and selecting a particular path that has a wider distance between target object scan points and other object scan points.

4. The method according to claim 1 wherein determining a straight target line includes using the equations:

5. The method according to claim 1 wherein identifying curve points for each other object includes determining an object distance for each of the objects from the straight target line, determining if each of the other objects is a predetermined safe distance from the target line, identifying and selecting the other objects whose distance to the target line is less than the safe distance, identify the curve points for the selected other objects and ignoring the curve points for the other objects whose distance from the target line is greater than the predetermined safe distance.

6. The method according to claim 1 further comprising continuing determining the virtual target path for the subject vehicle after the subject vehicle has passed the target object where the scan points include other object scan points.

7. The method according to claim 6 wherein determining the virtual steering path for the subject vehicle after it has passed the target object includes separating the other object scan points into groups based on their X-coordinate value and then identifying selected other objects scan points to identify curve points that are a safe distance from the selected points.

8. The method according to claim 1 wherein identifying a curved path that connects the curve points includes using a quadratic polynomial function.

9. The method according to claim 1 further comprising reducing the complexity of the plurality of scan points using a clustering algorithm before the scan points are separated into the target object scan points and the other object scan points.

10. The method according to claim 1 further comprising ignoring scan points that are outside of a predetermined safe distance from the subject vehicle.

11. The method according to claim 1 further comprising detecting a target vehicle as the target object from the other objects.

12. The method according to claim 1 further comprising calculating a corridor width between the target object and the other objects and aborting the evasive steering maneuver if the corridor width is less than a predetermined threshold width.

13. The method according to claim 1 wherein the at least one sensor is at least one LiDAR sensor.

14. A method for determining a virtual target path which is used to calculate an evasive steering path for a subject vehicle around a target vehicle in a travel path of the subject vehicle, said method comprising:

providing a plurality of scan points identifying detected objects from one or more sensors on the subject vehicle;

separating the plurality of scan points into target vehicle scan points received from the target vehicle and other object scan points received from other objects if they exist;

identifying a closest scan point from the target vehicle scan points that is the scan point that is the closest to the subject vehicle;

identifying a path point that is a predetermined safe distance from the closest scan point;

determining a straight target line adjacent to the target vehicle that goes through the path point and is parallel to a direction of the travel path of the subject vehicle before the subject vehicle follows the evasive steering path;

determining whether the plurality of scan points include the other object scan points;

making the evasive steering path the straight target line if no other object scan points exist;

determining a distance between the target line and each of the other objects identified by the other object scan points if other object scan points do exist;

determining whether all of the distances are greater than a predetermined threshold distance; and

making the evasive steering path the straight target line if all of the distances are greater than the threshold distance.

15. The method according to claim 14 further comprising determining whether the virtual target path is to a left side or a right side of the target vehicle prior to identifying the closest scan point.

16. The method according to claim 14 wherein determining a straight target line includes using the equations:

17. A method for determining a virtual target path which is used to calculate an evasive steering for a subject vehicle around a target vehicle in a travel path of the subject vehicle, said method comprising:

providing a plurality of scan points identifying detected objects from one or more sensors on the subject vehicle;

separating the plurality of scan points into target vehicle scan points received from the target vehicle and other object scan points received from other objects if they exist;

identifying a closest scan point from the target vehicle scan points that is the scan point that is the closest to the subject vehicle;

identifying a path point that is a predetermined safe distance from the closest scan point;

determining a straight target line adjacent to the target object that goes through the path point and is parallel to a direction of the travel path of the subject vehicle before the subject vehicle follows the evasive steering path;

identifying curve points for each other object whose distance is less than the predetermined threshold distance, where each curve point is a predetermined safe distance from the target vehicle and the other object; and

identifying a curved path that connects the curve points to be the evasive steering path using a quadratic polynomial function.

18. The method according to claim 17 wherein determining a straight target line includes using the equations:

19. The method according to claim 17 wherein identifying curve points for each other object includes determining an object distance for each of the objects from the straight target line, determining if each of the other objects is a predetermined safe distance from the target line, identifying and selecting the other objects whose distance to the target line is less than the safe distance, identify the curve points for the selected other objects and ignoring the curve points for the other objects whose distance from the target line is greater than the predetermined safe distance.

20. The method according to claim 17 further comprising continuing determining the virtual target path for the subject vehicle after the subject vehicle has passed the target object where the scan points include other object scan points.