SYSTEM AND METHOD FOR AUTOMATIC GUIDANCE CONTROL OF A VEHICLE

• US 20120215395A1
• Filed: 08/25/2011
• Published: 08/23/2012
• Est. Priority Date: 02/18/2011
• Status: Active Grant

• Current Assignee: Blue Leaf IP Incorporated (CNH Industrial N.V.)
• Original Assignee: Blue Leaf IP Incorporated (CNH Industrial N.V.)
• Inventors: AZNAVORIAN, Todd S., SCHUBERT, William L.
• Granted Patent: US 8,694,382 B2
• Time in Patent Office: Days
• US Class Current: 701/25
• CPC Class Codes: A01B 69/008 automatic
• 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 system and method is provided for adaptive control of at least one parameter of an auto guidance control algorithm for a vehicle. The parameters may be varied according to a previously established look up table, or automatically adapted through the use of control logic, such as a “fuzzy logic” algorithm. The control parameters that can be adaptively controlled include steered wheel turn rate, proportional valve current gain, line acquisition rate and/or auto guidance control valve current limits. The control algorithm responds to the vehicle'"'"'s operating parameters such as vehicle speed, tracking error, predicted heading, and hydraulic oil temperature to make adjustments to the auto guidance control parameters.

Claims

1. A method for automatically guiding a vehicle, the method comprising:

engaging an automatic guidance control system to steer a vehicle along a predetermined swath;

determining a swath path configuration of the predetermined swath to be subsequently travelled by the vehicle;

determining a cross track error for the vehicle relative to the predetermined swath;

determining a rate of change of the cross track error;

calculating a control parameter with the automatic guidance control system in response to the determined swath path configuration, the determined cross track error and the determined rate of change of the cross track error;

generating a control signal to steer the vehicle based on the calculated control parameter;

determining an operating condition for the vehicle;

calculating a response limit for the calculated control parameter in response to the determined operating condition;

adjusting the generated control signal by the calculated response limit; and

applying the adjusted control signal to the vehicle to steer the vehicle along the predetermined swath.

2. The method of claim 1 wherein generating a control signal comprises generating a pulse width modulation control signal.

3. The method of claim 1 wherein the swath path configuration is one of a straight path, a curved path or a sharply curved path.

4. The method of claim 1 wherein calculating a response limit comprises:

identifying a membership function for the determined operating parameter;

calculating a degree of membership for the determined operating parameter using the identified membership function; and

applying a fuzzy logic algorithm to determine the response limit based on the calculated degree of membership.

5. The method of claim 1 further comprising:

determining a vehicle travel speed;

determining a hydraulic oil temperature and engine speed;

determining a minimum turning radius associated with the vehicle; and

wherein calculating a control parameter comprises calculating a control parameter with the automatic guidance control system in response to the determined swath path configuration, the determined cross track error, the determined rate of change of the cross track error, the vehicle travel speed, the hydraulic oil temperature, the engine speed or the minimum turning radius associated with the vehicle.

6. The method of claim 1 wherein calculating a response limit comprises selecting a value of the response limit from a look up table based on the determined operating parameter.

7. The method of claim 1 wherein the control parameter is one of steered wheel turn rate, proportional valve current gain, line acquisition rate, or auto guidance control valve current limit.

8. The method of claim 1 wherein the determined operating parameter for the vehicle is one of vehicle travel speed, the cross track error, the rate of change of the cross track error, hydraulic oil temperature, engine speed, minimum turn radius for the vehicle or the swath path configuration.

9. The method of claim 8 wherein the determined operating parameter for the vehicle further includes one of vehicle dynamics, side hill operation of the vehicle, implement side draft associated with the vehicle or change in vehicle mass.

10. A method for automatically guiding a vehicle, the method comprising:

engaging an automatic guidance control system to steer a vehicle to acquire a predetermined swath;

measuring a speed of the vehicle;

determining a heading difference for the vehicle relative to a heading of the predetermined swath;

determining a rate of change of the heading difference;

determining a cross track error for the vehicle relative to the predetermined swath;

determining a rate of change of the cross track error;

calculating a control parameter with the automatic guidance control system in response to the measured vehicle speed, the determined heading difference, the determined rate of change of the heading difference, the determined cross track error and the determined rate of change of the cross track error;

generating a control signal to steer the vehicle based on the calculated control parameter;

determining an operating condition for the vehicle;

calculating a response limit for the calculated control parameter in response to the determined operating condition;

adjusting the generated control signal by the calculated response limit; and

applying the adjusted control signal to the vehicle to steer the vehicle to acquire the predetermined swath.

11. The method of claim 10 wherein calculating a response limit comprises:

identifying a membership function for the determined operating parameter;

calculating a degree of membership for the determined operating parameter using the identified membership function; and

applying a fuzzy logic algorithm to determine the response limit based on the calculated degree of membership.

12. The method of claim 10 further comprising:

determining a hydraulic oil temperature and engine speed;

determining a minimum turning radius associated with the vehicle;

determining a rate of curvature for the predetermined swath; and

wherein calculating a control parameter comprises calculating a control parameter with the automatic guidance control system in response to the measured vehicle speed, the determined heading difference, the determined rate of change of the heading difference, the determined cross track error and the determined rate of change of the cross track error, the hydraulic oil temperature, the engine speed, the determined rate of curvature or the minimum turning radius associated with the vehicle.

13. The method of claim 10 wherein determining a response limit comprises selecting a value of the response limit from a look up table based on the determined operating parameter.

14. The method of claim 10 wherein the control parameter is one of steered wheel turn rate, proportional valve current gain, line acquisition rate, or auto guidance control valve current limit.

15. The method of claim 10 wherein the determined operating parameter for the vehicle is one of the measured vehicle speed, the cross track error, the rate of change of the cross track error, a hydraulic oil temperature, an engine speed, a minimum turn radius for the vehicle or a rate of curvature for the predetermined swath.

16. The method of claim 15 wherein the determined operating parameter for the vehicle further includes one of vehicle dynamics, side hill operation of the vehicle, implement side draft associated with the vehicle or change in vehicle mass.

17. The method of claim 10 wherein generating a control signal comprises generating a pulse width modulation control signal.

18. The method of claim 10 further comprising determining whether the predetermined swath has been acquired using the cross track error.

19. An automatic guidance system for a vehicle comprising:

a global positioning system device to determine a position of the vehicle;

an input device, the input device being operational to enable an operator to enter information;

a first controller comprising a microprocessor to execute a computer program to calculate a control signal for the vehicle used to steer the vehicle in relation to a predetermined swath based on a control parameter; and

a second controller comprising a microprocessor to execute a computer program to generate an adjustment for the calculated control signal in response to a vehicle operating parameter.

20. The automatic guidance system of claim 19 wherein:

the computer program to generate an adjustment for the calculated control signal comprises a fuzzy logic algorithm;

the vehicle operating parameter includes at least one of a measured vehicle speed, a cross track error for the vehicle, the rate of change of the cross track error for the vehicle, a hydraulic oil temperature, an engine speed, a minimum turn radius for the vehicle or a rate of curvature for the predetermined swath;

the control parameter is one of steered wheel turn rate, proportional valve current gain, line acquisition rate, or auto guidance control valve current limit; and

the first controller comprises a microprocessor to execute a computer program to calculate the control parameter in response to at least one of a measured vehicle speed, a heading difference for the vehicle, a rate of change of the heading difference, a cross track error for the vehicle, a rate of change of the cross track error, a hydraulic oil temperature, an engine speed, a rate of curvature for the predetermined swath or a minimum turning radius associated with the vehicle.