AUTONOMOUS VEHICLE LATERAL CONTROL FOR PATH TRACKING AND STABILITY

• US 20170291638A1
• Filed: 04/07/2016
• Published: 10/12/2017
• Est. Priority Date: 04/07/2016
• Status: Active Grant

• Current Assignee: GM Global Technology Operations LLC (General Motors Company)
• Original Assignee: GM Global Technology Operations LLC (General Motors Company)
• Inventors: GUPTA, PINAKI
• Granted Patent: US 9,796,421 B1
• Time in Patent Office: Days
• CPC Class Codes: B60W 40/103 Side slip angle of vehicle body
• CPC Class Codes: B62D 15/025 Active steering aids, e.g. helping the driver by actively influencing the steering system after environment evaluation B62D1/28 takes precedence
• CPC Class Codes: B62D 6/003 in order to control vehicle yaw movement, i.e. around a vertical axis B62D6/007 takes precedence
• CPC Class Codes: G05D 1/021 specially adapted to land vehicles

Abstract

Methods, systems, and vehicles are provided for facilitating control of steering in autonomous vehicles. In accordance with one embodiment, an autonomous vehicle includes one or more wheel sensors and a processor. The one or more sensors are configured to obtain sensor data pertaining to a side slip of the autonomous vehicle. A dual mandate of desired path tracking & stability is achieved by using a combination of two linear controllers. The first controlled facilitates tracking whereas the second controller facilitates vehicle stability. When the stability event occurs a gradual shift towards the second controller occurs and with recovery from stability event gradual shift towards the first controller. Mimicking of driver behavior by changing the desired trajectory and dynamic control gain adaptation are also added.

Claims

1. A method comprising:

obtaining information pertaining to a side slip angle for an autonomous vehicle; and

controlling, via a processor, steering for the autonomous vehicle using a selected control algorithm based at least in part on the side slip angle, wherein the selected control algorithm is selected from a first control algorithm and a second control algorithm.

2. The method of claim 1, wherein the step of controlling the steering for the autonomous vehicle comprises:

controlling the steering using the first control algorithm, if the side slip angle is less than a first predetermined threshold; and

controlling the steering using the second control algorithm, if the side slip angle is greater than a second predetermined threshold.

3. The method of claim 1, wherein the step of controlling the steering for the autonomous vehicle comprises:

transitioning from controlling the steering using the first control algorithm to controlling the steering using the second control algorithm, if the side slip angle was previously less than the first predetermined threshold and is now greater than the first predetermined threshold.

4. The method of claim 1, wherein:

if the side slip angle is greater than a first predetermined threshold within a predetermined time window, then a more begin desired path is calculated in addition to using the first control algorithm.

5. The method of claim 1, wherein the step of controlling the steering for the autonomous vehicle comprises:

transitioning from controlling the steering using the second control algorithm to controlling the steering using the first control algorithm, if the side slip angle was previously greater than the first predetermined threshold and is now less than the first predetermined threshold.

6. The method of claim 5, wherein:

the first control algorithm and the second control algorithm are both used, simultaneously, to control the steering the slide slip angle is less than the first predetermined threshold during the transitioning; and

the first control algorithm is utilized without the second control algorithm to control steering after the slide slip angle has been less than the first predetermined threshold.

7. The method of claim 1, wherein the first control algorithm provides relatively more active steering as compared with the second control algorithm.

8. The method of claim 1, wherein:

the first control algorithm has a relatively higher priority for lane centering, as compared with the second control algorithm; and

the second control algorithm has a relatively higher priority for vehicle stability, as compared with the first control algorithm.

9. The method of claim 1, wherein:

the selection of the control algorithm is based at least in part on the side slip angle in combination with a gain scheduling function that incorporates a real time cost function based at least in part on the side slip angle.

10. A system comprising:

a sensor configured to obtain sensor data pertaining to a side slip angle for an autonomous vehicle; and

a processor configured to at least facilitate controlling steering for the autonomous vehicle using a selected control algorithm based at least in part on the side slip angle, wherein the selected control algorithm is selected from a first control algorithm and a second control algorithm.

11. The system of claim 10, wherein the processor is further configured to at least facilitate:

controlling the steering using the first control algorithm, if the side slip angle is less than a first predetermined threshold; and

controlling the steering using the second control algorithm, if the side slip angle is greater than a second predetermined threshold.

12. The system of claim 10, wherein the processor is further configured to at least facilitate:

transitioning from controlling the steering using the first control algorithm to controlling the steering using the second control algorithm, if the side slip angle was previously less than the first predetermined threshold and is now greater than the second predetermined threshold.

13. The system of claim 12, wherein the processor is further configured to at least facilitate:

using the first control algorithm and the second control algorithm, simultaneously, to control the steering for a predetermined amount of time after which the slide slip angle is greater than the second predetermined threshold during the transitioning; and

using the second control algorithm without the first control algorithm to control steering after the slide slip angle has been greater than the second predetermined threshold.

14. The system of claim 10, wherein the processor is further configured to at least facilitate:

transitioning from controlling the steering using the second control algorithm to controlling the steering using the first control algorithm, if the side slip angle was previously greater than the first predetermined threshold and is now less than the first predetermined threshold.

15. The system of claim 14, wherein the processor is further configured to at least facilitate:

using the first control algorithm and the second control algorithm, simultaneously, to control the steering for a predetermined amount of time after which the slide slip angle is less than the predetermined threshold during the transitioning; and

using the first control algorithm without the second control algorithm to control steering after the slide slip angle has been less than the predetermined threshold.

16. The system of claim 10, wherein the first control algorithm provides relatively more active steering as compared with the second control algorithm.

17. The system of claim 10, wherein:

the first control algorithm has a relatively higher priority for lane centering, as compared with the second control algorithm; and

the second control algorithm has a relatively higher priority for vehicle stability, as compared with the first control algorithm.

18. The system of claim 10, wherein:

if the side slip angle is greater than a first predetermined threshold within a predetermined time window, then a more begin desired path is calculated by the processor in addition to using the first control algorithm.

19. An autonomous vehicle comprising:

one or more sensors configured to obtain sensor data pertaining to a side slip angle for the autonomous vehicle; and

a processor configured to at least facilitate controlling steering for the autonomous vehicle using a selected control algorithm based at least in part on the side slip angle, wherein the selected control algorithm is selected from a first control algorithm and a second control algorithm.

20. The autonomous vehicle of claim 19, wherein the processor is further configured to at least facilitate:

controlling the steering using the first control algorithm, if the side slip angle is less than a first predetermined threshold; and

controlling the steering using the second control algorithm, if the side slip angle is greater than a second predetermined threshold.