Method and system for controlling steering deadband in a mobile machine

• US 20060015229A1
• Filed: 06/14/2005
• Published: 01/19/2006
• Est. Priority Date: 07/14/2004
• Status: Active Grant

• Current Assignee: Trimble Inc.
• Original Assignee: Trimble Navigation Limited (Trimble Inc.)
• Inventors: Kennedy, Keith, Lange, Arthur F., Gibson, Mark
• Granted Patent: US 7,363,132 B2
• Time in Patent Office: Days
• US Class Current: 701/41
• CPC Class Codes: B62D 1/00 Steering controls, i.e. means for initiating a change of direction of the vehicle
• CPC Class Codes: B62D 5/04 electrical, e.g. using an electric servo-motor connected to, or forming part of, the steering gear

Abstract

Embodiments of the present invention recite a method and system for controlling steering dead band in a mobile machine. In one embodiment, a first dead band value for actuating said steering mechanism in a first direction is determined. Then, a second dead band value for actuating said steering mechanism in a second direction is determined. The first dead band value and said second dead band value are then stored as discrete values.

Claims

1. A method for compensating for a dead band in a steering mechanism of a mobile machine, comprising:

determining a first dead band value for actuating said steering mechanism in a first direction;

determining a second dead band value for actuating said steering mechanism in a second direction; and

storing said first dead band value and said second dead band value as discrete values.

2. The method as recited in claim 1 wherein determining said first dead band value further comprises:

actuating said steering mechanism in said first direction to a first point until movement of the ground wheels of said mobile machine in said first direction is detected; and

noting the position of said steering mechanism corresponding to said first point.

3. The method as recited in claim 2 wherein determining said second dead band value further comprises:

actuating said steering mechanism in said second direction to a second point until movement of the ground wheels of said mobile machine in said second direction is detected; and

noting the position of said steering mechanism corresponding to said second point.

4. The method as recited in claim 3 wherein detecting movement of the ground wheels of said mobile machine is selected from the group consisting essentially of:

receiving a manual indication of the movement of the ground wheels of said mobile machine in said first direction and in said second direction; and

automatically detecting movement of the ground wheels of said mobile machine in said first direction and in said second direction.

5. The method as recited in claim 4 wherein detecting movement of the ground wheels of said mobile machine further comprises:

using a wheel angle sensor to detect movement of the ground wheels of said mobile machine in said first direction and in said second direction.

6. The method as recited in claim 4 wherein detecting movement of the ground wheels of said mobile machine further comprises:

detecting movement of said mobile machine from a desired direction to a second direction.

7. The method as recited in claim 6 wherein detecting movement from said desired direction further comprises:

receiving an indication of movement from said desired direction, said indication selected from the group consisting essentially of

a position determining system heading;

a compass heading; and

a yaw indication.

8. The method as recited in claim 4 wherein determining said second dead band value further comprises:

determining that said second dead band value is greater than said first dead band value;

initiating a free play set procedure wherein a succession of actuations of said steering mechanism in said second direction are initiated and in which the magnitude of each successive actuation is decreased until a first absence of movement of the ground wheels of said mobile machine is detected in response to an actuation of said steering mechanism in said second direction; and

noting a third point of said steering mechanism corresponding to the actuation of said steering mechanism at which said first absence of movement of the ground wheels of said mobile machine is detected in said second direction.

9. The method as recited in claim 8 wherein said free play set procedure further comprises:

initiating a succession of actuations of said steering mechanism in said first direction in which the magnitude of each successive actuation is decreased until a second absence of movement of the ground wheels of said mobile machine is detected in response to an actuation of said steering mechanism in said first direction; and

noting a fourth point of said steering mechanism corresponding to the actuation of said steering mechanism at which said second absence of movement of the ground wheels of said mobile machine is detected in said first direction.

10. The method as recited in claim 9 wherein detecting said first absence of movement and said second absence of movement is selected from the group consisting essentially of:

receiving a manual indication of said first absence of movement and said second absence of movement; and

automatically detecting said first absence of movement and said second absence of movement.

11. The method as recited in claim 9 wherein said dead band set procedure further comprises:

setting a first flag indicating that said second dead band value has been determined; and

setting a second flag indicating that said first dead band value has been determined.

12. The method as recited in claim 1 further comprising:

using said first dead band value and said second dead band value when steering said mobile machine in said first direction and in said second direction respectively.

13. The method as recited in claim 12 further comprising:

sending a signal corresponding to said first dead band value and said second dead band value to a controller used to actuate said steering mechanism.

14. The method as recited in claim 1 wherein said mobile machine comprises a vehicle having at least one of an agricultural application, a maintenance application, a construction application, a utility application, and a commercial application.

15. A system for controlling a mobile machine comprising:

an actuator for operating the steering mechanism of said mobile machine;

a controller coupled with said actuator for automatically actuating said steering mechanism in a first direction according to a first dead band value and for automatically actuating said steering mechanism in a second direction according to a second dead band value;

a determiner coupled with said steering mechanism for determining said first dead band value and said second dead band value; and

a storage medium coupled with said determiner and with said controller for storing said first dead band value and said second dead band value as discrete values.

16. The system of claim 15 further comprising:

a position sensor coupled with said steering mechanism and with said determiner for noting a first position of said steering mechanism that corresponds to a first point at which the ground wheels of said mobile machine are detected to move in response to moving said steering mechanism in said first direction.

17. The system of claim 16 wherein said position sensor is further for noting a second position of said steering mechanism that corresponds to a second point at which the ground wheels of said mobile machine are detected to move in response to moving said steering mechanism in said second direction.

18. The system of claim 17 further comprising:

an input for receiving a manual indication of the movement of the ground wheels of said mobile machine in said first direction and said second direction; and

a detector coupled with said mobile machine for automatically detecting the movement of the ground wheels of said mobile machine in said first direction and said second direction.

19. The system of claim 18, wherein said detector is for detecting a change in the angle of the ground wheels relative to said mobile machine.

20. The system of claim 18 wherein said detector is for detecting movement of said mobile machine from a desired direction to a second direction.

21. The system of claim 20 wherein said detector is selected from the group consisting essentially of:

a position determining system;

a compass; and

a yaw indicator.

22. The system of claim 18 wherein said determiner is further for determining that said second dead band value is greater than said first dead band value and for initiating a free play set procedure wherein the magnitude of a succession of actuations of said steering mechanism in said second direction is successively decreased until a first absence of movement of the ground wheels of said mobile machine is detected in response to an actuation of said steering mechanism in said second direction and wherein said position sensor notes a third position of said steering mechanism in response thereto.

23. The system of claim 22 wherein dead band set procedure further comprises successively decreasing the magnitude of a succession of actuations of said steering mechanism in said first direction until a second absence of movement of the ground wheels of said mobile machine is detected in response to an actuation of said steering mechanism in said first direction and wherein said position sensor notes a fourth position of said steering mechanism in response thereto.

24. The method as recited in claim 23 wherein detecting said first absence of movement and said second absence of movement is selected from the group consisting essentially of:

receiving a manual indication of said first absence of movement and said second absence of movement; and

automatically detecting said first absence of movement and said second absence of movement.

25. The system of claim 15 wherein said determiner is further for setting a first flag indicating that said second dead band value has been determined and for setting a second flag indicating that said first dead band value has been determined.

26. A dead band steering control system comprising:

a determiner for determining a first dead band value for actuating a steering mechanism of a mobile machine in a first direction and for determining a second dead band value for actuating said steering mechanism in a second direction; and

a storage medium for storing said first dead band value and said second dead band value as discrete values.

27. The dead band steering control system of claim 26 further comprising:

an input/output for receiving a first position of said steering mechanism, said first position corresponding to a first point to which said steering mechanism is actuated in said first direction until movement of the ground wheels of said mobile machine is detected and wherein said input/output is further for receiving a second position of said steering mechanism, said second position corresponding to a second point to which said steering mechanism is actuated in said second direction until movement of the ground wheels of said mobile machine is detected.

28. The dead band steering control system of claim 27 further comprising:

an input for receiving a manual indication of the movement of the ground wheels of said mobile machine in said first direction and said second direction; and

a detector for automatically detecting the movement of the ground wheels of said mobile machine in said first direction and in said second direction.

29. The dead band steering control system of claim 28 wherein said detector is for detecting the angle of the ground wheels relative to a longitudinal axis of said mobile machine.

30. The dead band steering control system of claim 28 wherein said detector is for detecting movement of said mobile machine away from a desired direction.

31. The dead band steering control system of claim 28 wherein said detector is selected from the group consisting essentially of:

a position determining system;

a compass; and

a yaw indicator.

32. The dead band steering control system of claim 28 wherein said determiner is further for:

determining that said second dead band value is greater than said first dead band value;

initiating a free play set procedure wherein a succession of actuations of said steering mechanism in said second direction is initiated and in which the magnitude of each successive actuation is decreased until a first absence of movement of the ground wheels of said mobile machine detected in response to an actuation of said steering mechanism in said second direction; and

noting a third point of said steering mechanism corresponding to the actuation of said steering mechanism at which said first absence movement of the ground wheels of said mobile machine is detected in said second direction.

33. The dead band steering control system of claim 32 wherein said free play set procedure further comprises:

initiating a succession of actuations of said steering mechanism in said first direction in which the magnitude of each successive actuation is decreased until a second absence of movement of the ground wheels of said mobile machine is detected in response to an actuation of said steering mechanism in said first direction; and

noting a fourth point of said steering mechanism corresponding to the actuation of said steering mechanism at said second absence of movement of the ground wheels of said mobile machine is detected in said first direction.

34. The method as recited in claim 33 wherein detecting said first absence of movement and said second absence of movement is selected from the group consisting essentially of:

receiving a manual indication of said first absence of movement and said second absence of movement; and

automatically detecting said first absence of movement and said second absence of movement.

35. The dead band steering control system of claim 33 wherein said determiner is further for:

setting a first flag indicating that said second dead band value has been determined in response to initiating said free play set procedure; and

setting a second flag indicating that said first dead band value has been determined.

36. The dead band steering control system of claim 26 further comprising:

an output for conveying said dead band first dead band value and said second dead band value to a control system for controlling said mobile machine.