System and method for controlling a ground vehicle

• US 6,901,319 B1
• Filed: 07/06/2004
• Issued: 05/31/2005
• Est. Priority Date: 07/06/2004
• Status: Active Grant

• Current Assignee: Deere & Company
• Original Assignee: Deere & Company
• Inventors: Miller, Byron K., Schick, Troy E., Nelson, Frederick W.
• Primary Examiner(s): Camby, Richard M.
• Application Number:
  US10/885,316
• Time in Patent Office: 329 Days
• Field of Search: 701/1, 701/41, 701/42, 701/48, 701/70, 701/71, 701/72, 701/80, 701/74, 701/75, 701/213, 701/300, 701/301, 180/197, 180/411, 180/443, 180/446, 303/139, 303/140, 303/146, 303/147, 280/5.51, 280/703, 280/707, 280/211, 700/44, 700/45, 700/46, 700/63
• US Class Current: 701/41
• CPC Class Codes: G05D 1/027 comprising intertial navigation means, e.g. azimuth detector inertial navigation G01C21/16; inertial navigation combined with non-inertial navigation instruments G01C21/165
• CPC Class Codes: G05D 1/0278 using satellite positioning signals, e.g. GPS
• CPC Class Codes: G05D 1/0891 specially adapted for land vehicles

Abstract

The present invention is a method for controlling a ground vehicle, for automated steering control of the vehicle or the like. The method of the present invention includes using a GPS receiver or the like and an inertial gyro or the like for providing automated steering control of the ground vehicle. A difference between a measured off-track error and a lateral error command is fed into a lateral error control loop, producing a lateral velocity command. Then, a difference between a measured lateral velocity and the lateral velocity command is fed into a lateral velocity control loop, producing a yaw rate command. Finally, a difference between a measured yaw rate, the yaw rate command, and a curved track yaw rate for the intended path of the vehicle is computed and fed into a yaw rate control loop, producing a valve command for steering the ground vehicle on or towards its intended path. Inputs such as measured wheel slip and the like are used to estimate the steering authority of the steered wheels of the vehicle; the estimated steering authority and/or the actions of a user driving the vehicle are used to adjust the gain of the yaw rate control loop.

Claims

1. A method for controlling a vehicle, comprising:

measuring a lateral error for the vehicle;

feeding a first control loop with a difference between the lateral error and a lateral error command, producing a lateral velocity command;

measuring a lateral velocity for the vehicle;

feeding a second control loop with a difference between the lateral velocity and the lateral velocity command, producing a yaw rate command;

measuring a yaw rate for the vehicle; and

feeding a third control loop with a difference between the yaw rate, the yaw rate command, and a curved track yaw rate for the intended path of the vehicle, producing a command for steering the vehicle.

2. The method as claimed in claim 1, wherein the lateral error of the vehicle is measured by comparing an intended position of the vehicle with positional data received by a global positioning system (GPS) receiver assembly.

3. The method as claimed in claim 1, wherein the lateral velocity of the vehicle is measured by comparing an actual course for the vehicle to an intended course, in combination with a forward speed for the vehicle.

4. The method as claimed in claim 3, wherein the actual course for the vehicle is determined from data received by a global positioning system (GPS) receiver assembly.

5. The method as claimed in claim 3, wherein the forward speed for the vehicle is determined from data received by a global positioning system (GPS) receiver assembly.

6. The method as claimed in claim 1, wherein the lateral velocity of the vehicle is measured by calculating a change in a plurality of lateral error measurements per unit time.

7. The method as claimed in claim 1, wherein the yaw rate is measured through direct feedback from an inertial gyro coupled with the vehicle.

8. The method as claimed in claim 1, wherein the yaw rate is measured by calculating a change in a plurality of positional measurements received by a global positioning system (GPS) receiver assembly per unit time.

9. The method as claimed in claim 1, further comprising:

measuring a wheel slip rate for the vehicle and using the wheel slip rate to estimate a steering authority for steered wheels of the vehicle,

wherein the estimated steering authority of the steered wheels is used to adjust the gain of the yaw rate control loop.

10. The method as claimed in claim 1, further comprising:

measuring a draft rate for an implement towed by the vehicle and

using the draft rate of the implement to estimate a steering authority for steered wheels of the vehicle,

wherein the estimated steering authority of the steered wheels is used to adjust the gain of the yaw rate control loop.

11. The method as claimed in claim 1, further comprising measuring at least one input from a user of the vehicle, wherein the at least one user input is used to adjust the yaw rate control loop.

12. The method as claimed in claim 1, wherein the command for steering the vehicle is a valve command.

13. The method as claimed in claim 1, wherein the command for steering the vehicle is for steering the vehicle on its intended path.

14. The method as claimed in claim 1, wherein the command for steering the vehicle is for steering the vehicle toward its intended path.

15. The method as claimed in claim 1, wherein at least one of the first, second, and third control loops are proportional gain control loops.

16. The method as claimed in claim 1, where the third control loop is a proportional control loop having variable gain.

17. A system for controlling a vehicle, comprising:

a global positioning system (GPS) receiver for receiving a positioning signal from a global positioning system and generating a position for the vehicle;

a processing system for processing the position information to obtain navigation control system information;

wherein the navigation control system feeds a first control loop with a difference between a measured lateral error and a lateral error command, producing a lateral velocity command;

feeds a second control loop with a difference between a measured lateral velocity and the lateral velocity command, producing a yaw rate command; and

feeds a third control loop with a difference between a measured yaw rate, the yaw rate command, and a curved track yaw rate for the intended path of the vehicle, producing a command for steering the vehicle.

18. A method for controlling a vehicle, comprising:

measuring a lateral error for the vehicle;

feeding a first control loop with a difference between the lateral error and a lateral error command, producing a lateral velocity command;

measuring a lateral velocity for the vehicle;

feeding a second control loop with a difference between the lateral velocity and the lateral velocity command, producing a yaw rate command;

measuring a yaw rate for the vehicle; and

feeding a third control loop with a difference between the yaw rate, the yaw rate command, and a curved track yaw rate for the intended path of the vehicle, producing a command for steering the vehicle, wherein the lateral error of the vehicle is measured by comparing an intended position of the vehicle with positional data received by a global positioning system (GPS) receiver assembly and wherein the lateral velocity of the vehicle is measured by comparing an actual course for the vehicle to an intended course, in combination with a forward speed for the vehicle.

19. The method as claimed in claim 18, wherein the yaw rate is measured through direct feedback from an inertial gyro coupled with the vehicle.

20. The method as claimed in claim 18, wherein the yaw rate is measured by calculating a change in a plurality of positional measurements received by a global positioning system (GPS) receiver assembly per unit time.