Path generation algorithm for automated lane centering and lane changing control system

• US 8,170,739 B2
• Filed: 06/20/2008
• Issued: 05/01/2012
• Est. Priority Date: 06/20/2008
• Status: Active Grant

• Current Assignee: GM Global Technology Operations LLC (General Motors Company)
• Original Assignee: GM Global Technology Operations LLC (General Motors Company)
• Inventors: Lee, Jin-Woo
• Primary Examiner(s): Dager, Jonathan M
• Application Number:
  US12/143,439
• Publication Number:
  US 20090319113A1
• Time in Patent Office: 1,411 Days
• Field of Search: None
• US Class Current: 701/25
• 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 15/0255 Automatic changing of lane, e.g. for passing another vehicle
• CPC Class Codes: G01C 21/12 executed aboard the object being navigated; Dead reckoning

Abstract

A system for providing path generation for automated lane centering and/or lane changing purposes. The system includes a desired path generation processor that receives signals detecting the roadway on which the vehicle is traveling, a request for a lane change, vehicle state information and a steering angle of the vehicle. The system also includes a path prediction processor that predicts the vehicle path based on vehicle state information including vehicle longitudinal speed, vehicle lateral speed, vehicle yaw-rate and vehicle steering angle. The desired path information and the predicted path information are compared to generate an error signal that is sent to a lane change controller that provides a steering angle signal to turn the vehicle and reduce the error signal. The desired path generation processor can use a fifth order polynomial equation to determine the desired path of the vehicle based on the input signals.

Claims

1. A system for determining a desired path for vehicle steering, said system comprising:

a plurality of vehicle sensors and detectors configured to detect a travel lane of a roadway that the vehicle is travelling in and providing lane identification signals;

a desired path generation processor configured to respond to the lane signals, a request for a lane change and a steering angle signal of the steering angle of the vehicle, said desired path generation processor configured to generate a desired path of the vehicle and to provide an output signal including a longitudinal distance that the lane change will take, a lateral distance that the lane change will take and an angle for the lane change;

a path prediction processor configured to respond to vehicle state signals including vehicle lateral speed, vehicle longitudinal speed, vehicle yaw-rate and steering angle, said path prediction processor configured to predict a path of the vehicle based on the lateral vehicle speed, the longitudinal vehicle speed, the vehicle yaw-rate and the steering angle, said path prediction processor configured to provide an output signal identifying the predicted path of the vehicle; and

a comparator configured to compare the output signal from the desired path generation processor and the output signal from the path prediction processor and to provide an error signal of the difference between the desired path and the predicted path of the vehicle.

2. The system according to claim 1 further comprising a lane change controller configured to respond to the error signal, said lane change controller processor configured to provide the steering angle signal for steering the vehicle to minimize the error signal.

3. The system according to claim 2 further comprising a vehicle steering control sub-system configured to respond to the steering angle signal from the lane change controller, said vehicle steering control sub-system using the steering angle signal to steer the vehicle.

4. The system according to claim 3 wherein some of the vehicle sensors measure vehicle motion and provide measurement signals of vehicle speed, vehicle yaw-rate and steering angle.

5. The system according to claim 4 further comprising a vehicle state estimation processor configured to respond to the vehicle measurement signals and to provides filtered signals of the vehicle lateral speed, the vehicle longitudinal speed and the vehicle yaw-rate to the path prediction processor.

6. The system according to claim 1 further comprising a lane mark detection processor configured to respond to signals from a forward vision camera that detects lanes that the vehicle is travelling in, said lane mark detection processor configured to identify lane marks in the lanes and to provide the lane signals to the desired path generation processor.

7. The system according to claim 1 wherein the desired path generation processor is configured to determines the desired path using a fifth order polynomial equation.

8. The system according to claim 1 wherein the desired path generation processor determines the desired path as a plurality of segments if an obstacle is detected in the desired path, said segments including a first segment between the vehicle position and the obstacle and a second segment between the obstacle and the remainder of the desired vehicle path.

9. The system according to claim 1 wherein the desired path generation processor receives a lateral offset and heading angle relative to the road, and road curvature information to generate the desired path for a vehicle traveling around a curve.

10. The system according to claim 1 wherein the desired path generation processor generates the desired path as a virtual path beyond the sensor range of the sensors in the vehicle that detect the roadway.

11. A system for determining a desired path for vehicle steering an autonomous or semi-autonomous vehicle, said system comprising:

a plurality of vehicle sensors and detectors configured to detect a travel lane of a roadway that the vehicle is traveling in and providing lane identification signals, said sensors also providing measurement and motion signals of vehicle speed and vehicle yaw-rate;

a desired path generation processor configured to respond to the lane signals, a driver request for a lane change and a steering angle of the vehicle, said desired path generation processor configured to generate a desired path of the vehicle and providing an output signal including a longitudinal distance that the lane change will take, a lateral distance that the lane change will take and an angle for the lane change, said desired path generation processor configured to determine the desired path using a fifth order polynomial equation;

a path prediction processor configured to respond to vehicle state signals including vehicle lateral speed, vehicle longitudinal speed, vehicle yaw-rate and vehicle steering angle, said path prediction processor configured to predict a path of the vehicle based on the lateral vehicle speed, the longitudinal vehicle speed, the vehicle yaw-rate and the steering angle, said path prediction processor configured to provide an output signal identifying the predicted path of the vehicle;

a comparator configured to compare the output signal from the desired path generation processor and the output signal from the path prediction processor and to provides an error signal of the difference between the desired path and the predicted path of the vehicle;

a lane change controller configured to respond to the error signal, said lane change controller providing the steering angle signal for steering the vehicle to minimize the error signal; and

a vehicle steering control sub-system configured to respond to the steering angle signal from the lane change controller, said vehicle steering control sub-system using the steering angle signal to steer the vehicle.

12. The system according to claim 11 further comprising a vehicle state estimation processor configured to respond to the vehicle measurement and motion signals and to provides filtered signals of the vehicle lateral speed, the vehicle longitudinal speed, the vehicle yaw-rate and the vehicle steering angle to the path prediction processor.

13. The system according to claim 11 further comprising a lane mark detection processor configured to respond to signals from the vehicle sensors and detectors that detect lanes that the vehicle is travelling in, said lane mark detection processor configured to identify lane marks in the lanes and to provide the lane signals to the desired path generation processor.

14. The system according to claim 11 wherein the desired path generation processor determines the desired path as a plurality of segments if an obstacle is detected in the desired path, said segments including a first segment between the vehicle position and the obstacle and a second segment between the obstacle and the remainder of the desired vehicle path.

15. The system according to claim 11 wherein the desired path generation processor receives road curvature information to generate the desired path for a vehicle traveling around a curve.

16. The system according to claim 11 wherein the desired path generation processor generates the desired path as a virtual path beyond the sensor range of the sensors in the vehicle that detect the roadway.

17. A system for determining a desired path for steering a vehicle, said system comprising:

a plurality of vehicle sensors and detectors configured to detect a travel lane of a roadway that the vehicle is traveling in and providing lane identification signals;

a desired path generation processor configured to respond to the lane signals, a request for a lane change and a steering angle signal of the steering angle of the vehicle, said desired path generation processor configured to generate a desired path of the vehicle and to provide an output signal including a longitudinal distance the lane change will take, a lateral distance that the lane change will take and an angle for the lane change, said desired generation processor configured to determine the desired path using a fifth order polynomial equation, wherein the desired path generation processor is configured to receive a lateral offset and heading angle relative to the road, and road curvature information to generate the desired path for a vehicle traveling around a curve;

a path prediction processor configured to respond to vehicle state signals including vehicle lateral speed, vehicle longitudinal speed, vehicle yaw-rate and steering angle, said path prediction processor configured to predict a path of the vehicle based on the lateral vehicle speed, the longitudinal vehicle speed, the vehicle yaw-rate and the steering angle, said path prediction processor configured to provide an output signal identifying the predicted path of the vehicle; and

a comparator configured to compare the output signal from the desired path generation processor and the output signal from the path prediction processor and to provide an error signal of the difference between the desired path and the predicted path of the vehicle.

18. The system according to claim 17 further comprising a lane change controller configured to respond to longitudinal distance, lateral distance and sensor angle error signals and providing the steering angle signal for steering the vehicle.

19. The system according to claim 17 further comprising a lane mark detection processor configured to respond to the signals from the vehicle sensors and detectors that detect the lane that the vehicle is traveling in, said lane mark detection processor configured to identify lane marks in the lanes and providing the lane signals to the desired path generation processor.