UNIFIED MOTION PLANNING ALGORITHM FOR AUTONOMOUS DRIVING VEHICLE IN OBSTACLE AVOIDANCE MANEUVER

• US 20150353082A1
• Filed: 06/05/2014
• Published: 12/10/2015
• Est. Priority Date: 06/05/2014
• Status: Active Grant

• Current Assignee: Carnegie Mellon University, GM Global Technology Operations LLC (General Motors Company)
• Original Assignee: Carnegie Mellon University
• Inventors: LEE, JIN-WOO, MUDALIGE, UPALI PRIYANTHA, DOLAN, JOHN M., GU, TIANYU
• Granted Patent: US 9,457,807 B2
• Time in Patent Office: Days
• US Class Current: 1/1
• CPC Class Codes: B60W 10/20 including control of steering systems
• CPC Class Codes: B60W 2556/50 of positioning data, e.g. GPS [Global Positioning System] data
• CPC Class Codes: B60W 2720/10 Longitudinal speed
• CPC Class Codes: B60W 30/09 Taking automatic action to avoid collision, e.g. braking and steering
• CPC Class Codes: B60W 30/10 Path keeping cruise control for automatically following a preceding vehicle B60W30/165

Abstract

A method for automated lane centering and/or lane changing purposes for a vehicle traveling on a roadway that employs roadway points from a map database to determine a reference vehicle path and sensors on the vehicle for detecting static and moving objects to adjust the reference path. The method includes reducing the curvature of the reference path to generate a reduced curvature reference path that reduces the turning requirements of the vehicle and setting the speed of the vehicle from posted roadway speeds from the map database. The method also includes providing multiple candidate vehicle paths and vehicle speeds to avoid the static and moving objects in front of the vehicle.

Claims

1. A method for generating a desired path for a vehicle to follow along a roadway, said vehicle including a map database and/or a lane detection system, said method comprising:

providing roadway measurement values from the map database and/or the lane detection sensing system that identify locations on the roadway;

determining a reference path using the roadway measurement values for the vehicle to follow along the roadway;

determining a reference speed of the vehicle from a posted roadway speed from the map database;

determining that an object creates a potential collision problem with the vehicle on the reference path and at the reference speed; and

adjusting the reference path and/or the reference speed to avoid the object.

2. The method according to claim 1 wherein determining the reference path using the roadway measurement values includes adjusting the position of the measurement values relative to the roadway so that adjacent values are substantially an equal distance apart.

3. The method according to claim 1 further comprising reducing a curvature of the reference path to generate a reduced curvature reference path that reduces the turning requirements of the vehicle.

4. The method according to claim 3 wherein reducing the curvature of the reference path includes minimizing a cost function where the roadway measurement values are selectively adjusted at high curvature locations along the reference path.

5. The method according to claim 4 wherein minimizing the cost function includes minimizing the cost function as:

6. The method according to claim 1 wherein determining the speed of the vehicle includes identifying a roadway curvature value at each roadway measurement value and for each roadway measurement value determining the vehicle speed as:

7. The method according to claim 1 further comprising identifying that a request for a lane change has been made and performing a lane change maneuver by directing the reference path into an adjacent lane.

8. The method according to claim 1 wherein determining that an object creates a potential collision problem includes determining that a static object is a predetermined distance from the reference path and determining a modified reference path a desired distance from the static object.

9. The method according to claim 8 wherein determining the modified reference path a desired distance from the static object includes identifying multiple candidate modified reference paths and minimizing a cost function to determine an optimum candidate modified reference path.

10. The method according to claim 9 wherein minimizing the cost function includes:

11. The method according to claim 1 wherein determining that an object creates a potential collision problem includes determining that a moving object is in front of the vehicle in the roadway and adjusting the reference speed to avoid the moving object.

12. The method according to claim 11 wherein adjusting the reference speed includes identifying multiple candidate speeds and minimizing a cost function that selects one of the multiple candidate speeds that is close to the reference speed.

13. The method according to claim 12 wherein minimizing the cost function includes:

14. The method according to claim 1 wherein the vehicle includes at least one forward-looking camera, said method further comprising providing roadway measurement values from the camera that identify locations on the roadway and using the roadway measurement values from the camera to determine that the vehicle has deviated from the reference path.

15. The method according to claim 14 further comprising determining a short segment path that will bring the vehicle back to the reference path.

16. The method according to claim 14 wherein determining a short segment path includes modeling a local closed-loop trajectory as a fifth-order polynomial path model and a third-order polynomial speed model.

17. A method for generating a desired path for a vehicle to follow along a roadway, said vehicle including at least one forward-looking camera, and a lane detection system and/or a map database, said method comprising:

providing roadway measurement values from the map database and/or the lane detection sensing system that identify locations on the roadway;

determining a reference path using the roadway measurement values for the vehicle to follow along the roadway;

determining a reference speed of the vehicle from a posted roadway speed from the map database;

determining that an object creates a potential collision problem with the vehicle on the reference path and at the reference speed; and

adjusting the reference path and/or the reference speed to avoid the object.

reducing the curvature of the reference path to generate a reduced curvature reference path that reduces the turning requirements of the vehicle;

providing roadway values from the camera that identify locations on the roadway and using the roadway values from the camera to determine that the vehicle has deviated from the reference path; and

determining a short segment path that will bring the vehicle back to the reference path

18. The method according to claim 17 wherein determining a short segment path includes modeling a local closed-loop trajectory as a fifth-order polynomial path model and a third-order polynomial speed model.

19. The method according to claim 17 wherein determining that an object creates a potential collision problem includes determining that a static object is a predetermined distance from the reference path and determining a modified reference path a desired distance from the static object.

20. The method according to claim 17 wherein determining that an object creates a potential collision problem includes determining that a moving object is in front of the vehicle in the roadway and adjusting the vehicle speed to avoid the moving object.