Line acquisition path generation

• US 10,209,714 B2
• Filed: 04/10/2017
• Issued: 02/19/2019
• Est. Priority Date: 04/12/2016
• Status: Active Grant

• Current Assignee: Agjunction LLC (Kubota Corporation)
• Original Assignee: Agjunction LLC (Kubota Corporation)
• Inventors: Medagoda, Eran D. B., Sullivan, Timothy J., Dang, Tri M.
• Primary Examiner(s): Lee, Tyler J
• Application Number:
  US15/483,061
• Publication Number:
  US 20170293303A1
• Time in Patent Office: 680 Days
• CPC Class Codes: A01B 69/006 derived from the steering of the tractor
• CPC Class Codes: A01B 69/008 automatic
• CPC Class Codes: B62D 15/029 Steering assistants using warnings or proposing actions to the driver without influencing the steering system
• CPC Class Codes: B62D 6/002 computing target steering angles for front or rear wheels B62D7/159 takes precedence
• CPC Class Codes: G01C 21/20 Instruments for performing navigational calculations G01C21/24, G01C21/26 take precedence
• CPC Class Codes: G05D 1/021 specially adapted to land vehicles
• CPC Class Codes: G05D 1/0212 with means for defining a desired trajectory involving a plurality of land vehicles G05D1/0287
• CPC Class Codes: G05D 1/0278 using satellite positioning signals, e.g. GPS

Abstract

A line acquisition system predicts and displays an acquisition path to reduce the uncertainty surrounding the path taken by a vehicle when acquiring a destination path. The line acquisition system calculates the drivable acquisition path based on the current states of the vehicle, such as position, speed, heading, and curvature. The line acquisition system continually updates and displays the acquisition path as the vehicle is manually steered by the user. When the user engages a steering controller, the last calculated acquisition path is used to automatically steer the vehicle onto the destination path. Displaying the acquisition path allows the user to observe, prior to automatic steering engagement, the path the vehicle would take from its current state to the destination. The user can then decide whether the predicted acquisition path will interfere with terrain or obstacles that the user wishes to avoid.

Claims

1. A line acquisition system for automatically steering a vehicle, comprising:

a hardware processor to;

identify a destination path;

receive sensor data from a global positioning system (GPS);

calculate a current position of the vehicle based on the GPS sensor data;

calculate a simulated acquisition path from the current position of the vehicle to the destination path;

store the simulated acquisition path in memory;

repeatedly recalculate the acquisition path for a current position of the vehicle relative to the destination path;

display the acquisition path on a user interface; and

send the acquisition path to an automatic steering controller based on a selection of the displayed acquisition path.

2. The line acquisition system of claim 1, the processor further to:

incrementally calculate new simulated states of the vehicle toward the destination path based on error states between previous simulated states of the vehicle and the destination path; and

store the new simulated states and previous simulated states of the vehicle as the simulated acquisition path.

3. The line acquisition system of claim 1, the processor further to:

identify a curvature and curvature rate for the vehicle; and

calculate the simulated acquisition path based on the curvature and curvature rate.

4. The line acquisition system of claim 1, the processor further to:

continuously calculate new simulated acquisition paths for new positions of the vehicle; and

display the new simulated acquisition paths on the user interface.

5. The line acquisition system of claim 1, the hardware processor further to:

display an area on the user interface;

display a section of the area previously worked by the vehicle; and

display the destination path and the acquisition path with the area and the section of the area previously worked by the vehicle.

6. The line acquisition system of claim 1, the processor further to:

send steering commands to the automatic steering controller to steer the vehicle along the acquisition path until reaching the destination path and then send steering commands to the automatic steering controller to steer the vehicle along the destination path.

7. A line acquisition system for automatically steering a vehicle, comprising:

a hardware processor configured to;

identify a destination path;

receive sensor data from a global positioning system (GPS);

calculate a current location and current heading of the vehicle from the GPS sensor data;

calculate a heading error between the current heading of the vehicle and a heading of the destination path;

calculate a cross-track error between the current location of the vehicle and the destination path;

predict incremental positions of the vehicle based on the heading error, cross-track error, a curvature of the vehicle and a curvature rate of the vehicle; and

use the incremental positions of the vehicle as a simulated acquisition path from the vehicle to the destination path;

store the simulated acquisition path in memory;

repeatedly recalculate the acquisition path for a current position of the vehicle relative to the destination path;

display the acquisition path on a user interface; and

send the acquisition path to an automatic steering controller based on a selection of the displayed acquisition path.

8. A line acquisition system for automatically steering a vehicle, comprising:

a hardware processor to;

identify a destination path;

receive sensor data from a global positioning system (GPS);

calculate a current location and current heading of the vehicle from the GPS sensor data;

calculate a simulated acquisition path from the current position and heading of the vehicle to the destination path;

store the simulated acquisition path in memory;

repeatedly recalculate the acquisition path for a current position of the vehicle relative to the destination path;

display the acquisition path on a user interface; and

send the acquisition path to an automatic steering controller based on a selection of the displayed acquisition path, wherein the processor is further to calculate the simulated acquisition path based on a vehicle model expressed as;

{dot over (x)}=V cos(ψ

)

{dot over (y)}=V sin(ψ

)

{dot over (ψ

)}=Vκ

_d

where;

x and y are positional coordinates of the vehicle;

ψ

is a heading of the vehicle;

V is a speed of the vehicle;

κ

_d is a curvature demand for the vehicle, where

κ

_d=K₁e_ψ

+K₂e_ct+K₃∫

e_ctdt;

K₁ is a controller gain acting on a heading error e_ψ

;

K₂ is a controller gain acting on a cross-track error e_ct; and

K₃ is a controller gain acting on a cross-track error integral ∫

e_ct dt.

9. A computer program for controlling a vehicle, the computer program comprising a set of instructions operable to:

identify a destination path;

predict incremental positions of the vehicle from different locations of the vehicle to the destination path;

calculate a heading error between a heading of the vehicle and a heading of the destination path for a current one of the predicted incremental positions of the vehicle;

calculate a cross-track error between a current location of the vehicle and the destination path for a current one of the predicted incremental positions of the vehicle;

predict a next one of the incremental positions of the vehicle based on the heading error and cross-track error;

use the incremental positions of the vehicle as acquisition paths from different locations of the vehicle to the destination path;

display the different acquisition paths for the different locations of the vehicle on a user interface;

detect a request to automatically steer the vehicle; and

use one of the acquisition paths for a current location of the vehicle to automatically steer the vehicle to the destination path.

10. The computer program of claim 9, wherein the instructions are further operable to:

identify a curvature and curvature rate for the vehicle;

identify a distance and heading of the vehicle relative to the destination path; and

predict the incremental positions of the vehicle based on the curvature, curvature rate, distance, and heading of the vehicle.

11. The computer program of claim 9, wherein the instructions are further operable to:

receive selection of one of the acquisition paths displayed on the user interface; and

generate steering commands to automatically steer the vehicle along the selected one of the acquisition paths until reaching the destination path and then automatically steer the vehicle along the destination path.

12. The computer program of claim 9, wherein the instructions are further operable to display an area on the user interface;

display a section of the area previously worked by the vehicle; and

display the destination path and the acquisition path with the area and the section of the area previously worked by the vehicle.

13. A computer program for controlling a vehicle, the computer program comprising a set of instructions operable to:

identify a destination path;

predict different acquisition paths from different locations of the vehicle to the destination path;

display the different acquisition paths for the different locations of the vehicle on a user interface;

detect a request to automatically steer the vehicle; and

use one of the acquisition paths for a current location of the vehicle to automatically steer the vehicle to the destination path, wherein the instructions are further operable to predict the acquisition paths based on a vehicle model expressed as;

{dot over (x)}=V cos(ψ

)

{dot over (y)}=V sin(ψ

)

{dot over (ψ

)}=Vκ

_d

where

x and y are positional coordinates of the vehicle;

ψ

is a heading of the vehicle;

V is a speed of the vehicle;

κ

_d is a curvature demand for the vehicle, where

κ

_d=K₁e_ψ

+K₂e_ct+K₃∫

e_ctdt;

K₁ is a controller gain acting on a heading error e_ψ

;

K₂ is a controller gain acting on a cross-track error e_ct; and

K₃ is a controller gain acting on a cross-track error integral ∫

e_ct dt.

14. A computer program stored on a non-transitory storage medium, the computer program comprising a set of instructions, when executed by a hardware processor, cause the hardware processor to:

generate error states for simulated states of a vehicle from a destination path;

generate desired vehicle curvatures based on the error states;

generate the simulated states of the vehicle based on the desired vehicle curvatures;

use the simulated vehicle states to generate acquisition paths from different locations of the vehicle to the destination path; and

display the acquisition paths on a user interface to enable a vehicle driver to view how an automatic steering controller would steer the vehicle onto the destination path.

15. The computer program of claim 14, wherein the set of instructions, when executed by a hardware processor, further cause the hardware processor to calculate cross-track error states and heading error states between the simulated states of the vehicle and the destination path.

16. The computer program of claim 14, wherein the set of instructions, when executed by a hardware processor, further cause the hardware processor to generate the simulated states of the vehicle based on the desired vehicle curvatures and a measured curvature and curvature rate of the vehicle.

17. The computer program of claim 14, wherein the set of instructions, when executed by a hardware processor, further cause the hardware processor to:

detect a request to activate an automatic steering controller; and

generate steering commands that cause the automatic steering controller to steer the vehicle along one of the acquisition paths for a current location of the vehicle onto the destination path.