Method and system for controlling steering deadband in a mobile machine

• US 20060015228A1
• Filed: 12/21/2004
• Published: 01/19/2006
• Est. Priority Date: 07/14/2004
• Status: Active Grant

• Current Assignee: Trimble Navigation Limited (Trimble Inc.)
• Original Assignee: Trimble Navigation Limited (Trimble Inc.)
• Inventors: Lange, Arthur F.
• Granted Patent: US 7,640,088 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 15/00 Steering not otherwise provided for
• CPC Class Codes: B62D 5/0457 characterised by control features of the drive means as such
• CPC Class Codes: G05D 1/0278 using satellite positioning signals, e.g. GPS

Abstract

A method and system for controlling steering dead band in a mobile machine is described. The method includes measuring the dead band, storing a value corresponding to thereto, and applying the dead band value to a controller of a steering mechanism. The steering mechanism is thus controlled according to the dead band value to compensate for the dead band.

Claims

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

measuring said dead band;

storing a value corresponding to said dead band; and

applying said dead band value to a controller of said steering mechanism wherein said steering mechanism is controlled according to said dead band value to compensate for said dead band.

2. The method as recited in claim 1 wherein said measuring comprises:

actuating said steering mechanism in a first direction to a first point at which movement of ground wheels of said mobile machine, in response to said first direction actuating, is first detected;

noting a first position of said steering mechanism corresponding to said first point;

actuating said steering mechanism in a second direction to a second point at which movement of ground wheels, in response to said second direction actuating, is first detected;

noting a second position of said steering mechanism corresponding to said determining; and

storing a difference between said second position and said first position of said steering mechanism wherein said difference corresponds to said value.

3. The method as recited in claim 2 wherein said steering mechanism comprises a steering wheel and wherein said difference corresponds to one or more of an angle, a secant scribed by said angle and a circumference corresponding to said steering wheel, and a partial circumferential distance corresponding to a portion of said circumference scribed by said angle.

4. The method as recited in claim 2 wherein said dead band value corresponds to a first said dead band value, said method further comprising:

upon said noting said second position of said steering mechanism, actuating said steering mechanism in said first direction to a third point at which movement of said ground wheels, in response to said first direction actuating to a third point, is first detected;

noting a third position of said steering mechanism corresponding to said third point; and

storing a difference between said third position and said second position of said steering mechanism wherein said difference between said third position and said second position corresponds to a second said dead band value.

5. The method as recited in claim 4, further comprising comparing said first and said second dead band values wherein:

upon determining that said first and said second dead band values are substantially equal, said storing comprises storing the same value for said first and said second dead band values; and

upon determining that said first and said second dead band values are not equal, said storing comprises one or more of;

storing said first value;

storing said second value; and

storing an average of said first value and said second value.

6. The method as recited in claim 1 wherein said applying comprises sending a signal corresponding to said value to said controller, wherein said controller controls said steering mechanism according to said signal.

7. The method as recited in claim 6 wherein said controller comprises a servo system and wherein said steering mechanism comprises an electric motor driving system coupled to and for driving a steering wheel device wherein said servo system controls said electric motor to actuate said steering wheel to automatically compensate for said dead band.

8. The method as recited in claim 1 wherein said mobile machine comprises a vehicle wherein said vehicle has application in one or more of agriculture, maintenance, construction, utility, and commercial.

9. A system for controlling for dead band in the automatic steering mechanism of a mobile machine, comprising:

an actuator for operating said steering mechanism;

a controller for automatically controlling said actuator according to a stored value corresponding to said dead band; and

a storage medium for storing said value.

10. The system as recited in claim 9 wherein said actuator comprises an electric steering component coupled to and for driving a steering wheel device of said mobile machine wherein said electric steering component actuate said steering wheel device to automatically compensate for said dead band.

11. The system as recited in claim 10, further comprising a position determining component for determining the geographic position of said mobile machine wherein said electric steering component for controlling the steering mechanism of said mobile machine in response to a message wherein said control component generates said message in response to receiving position data from said position determining component.

12. The system as recited in claim 11 wherein said position determining system comprises one or more of a ground based position determining system and a satellite based position determining system.

13. The system as recited in claim 12 wherein said satellite based position determining system comprises one or more of a global positioning system (GPS) system, a differential GPS system, a real-time kinematics (RTK) system, a networked RTK system, a GLONASS system, and a Galileo system.

14. The system as recited in claim 10 wherein said electric steering component comprises a motor coupled with a steering column of said mobile machine and wherein said actuator device comprises a drive wheel which controls a steering wheel of said steering mechanism.

15. The system as recited in claim 9 further comprising a detection component for determining when a user is steering said mobile machine and for initiating disengagement of said steering mechanism and said system in response to said determining.

16. The system as recited in claim 9 wherein said mobile machine comprises a vehicle wherein said vehicle has application in one or more of agriculture, maintenance, construction, utility, and commerce.

17. An steering controller for a vehicle, comprising:

a guidance mechanism for determining a course correction for said vehicle based upon position data received from a position determining system;

a steering controller coupled with said guidance mechanism and for generating a first steering command based upon said course correction, and wherein said first steering command is conveyed to one or more of an electric steering component and a hydraulic steering component coupled with a steering mechanism to actuate said steering mechanism to automatically steer said vehicle according to said course correction; and

a compensator mechanism coupled to said steering controller and providing thereto a stored value corresponding to a dead band of said steering mechanism wherein said steering controller generates a second steering command based on said dead band value and wherein second steering command is conveyed to one or more of an electric steering component and a hydraulic steering component coupled with a steering mechanism to actuate said steering mechanism to automatically steer said vehicle according to said dead band value.

18. The steering controller as recited in claim 17 wherein said position determining system is one or more of ground based and satellite based.

19. The steering controller as recited in claim 17 wherein said satellite based position determining component is selected from the group consisting of a global positioning system (GPS) system, a differential GPS system, a real-time kinematics (RTK) system, a networked RTK system, a GLONASS system, and a Galileo system.

20. The steering controller as recited in claim 17 has application in one or more of agriculture, maintenance, construction, utility, and commerce.

21. The steering controller as recited in claim 17 wherein said electric steering component comprises:

an electric motor coupled with a steering column of said vehicle; and

an actuator device coupled with said electric motor and configured to control said steering mechanism.

22. The steering controller as recited in claim 21 wherein said electric motor is selected from the group consisting of a permanent magnet brush direct current (DC) motor, a brushless DC motor, a stepper motor, and an alternating current (AC) servo motor.

23. The steering controller as recited in claim 17 wherein said actuator device comprises a drive wheel which is coupled with a steering wheel of said vehicle.

24. The steering controller as recited in claim 17 wherein said electric steering component further comprises a detection component for determining when a user is steering said vehicle and for initiating disengagement of said electric steering component and said hydraulic steering component in response to said determining.

25. A method for controlling an vehicle comprising:

determining a geographic position of said vehicle;

automatically generating a first steering command based upon said geographic position;

steering said vehicle according to said first steering command; and

compensating for a dead band in the steering mechanism of said vehicle.

26. The method as recited in claim 25 wherein said compensating comprises:

measuring said dead band;

storing a value corresponding to said dead band;

automatically generating a second steering command based upon said dead band value; and

steering said vehicle according to said second steering command.

27. The method as recited in claim 26 wherein said measuring comprises:

actuating said steering mechanism in a first direction to a first point at which movement of ground wheels of said mobile machine, in response to said first direction actuating, is first detected;

noting a first position of said steering mechanism corresponding to said first point;

actuating said steering mechanism in a second direction to a second point at which movement of ground wheels, in response to said second direction actuating, is first detected;

noting a second position of said steering mechanism corresponding to said determining; and

storing a difference between said second position and said first position of said steering mechanism wherein said difference corresponds to said value.

28. The method as recited in claim 27 wherein said steering mechanism comprises a steering wheel and wherein said difference corresponds to one or more of an angle, a secant scribed by said angle and a circumference corresponding to said steering wheel, and a partial circumferential distance corresponding to a portion of said circumference scribed by said angle.

29. The method as recited in claim 27 wherein said dead band value corresponds to a first said dead band value, said method further comprising:

upon said noting said second position of said steering mechanism, actuating said steering mechanism in said first direction to a third point at which movement of said ground wheels, in response to said first direction actuating to a third point, is first detected;

noting a third position of said steering mechanism corresponding to said third point; and

storing a difference between said third position and said second position of said steering mechanism wherein said difference between said third position and said second position corresponds to a second said dead band value.

30. The method as recited in claim 29, further comprising comparing said first and said second dead band values wherein:

upon determining that said first and said second dead band values are substantially equal, said storing comprises storing the same value for said first and said second directions; and

upon determining that said first and said second dead band values are not equal, said storing comprises one or more of;

storing said first value;

storing said second value; and

storing an average of said first value and said second value.

31. The method as recited in claim 26 wherein said automatically generating a second steering command comprises sending a signal corresponding to said value to a controller, wherein said controller controls said steering mechanism according to said signal.

32. The method as recited in claim 31 wherein said controller comprises a servo system and wherein said steering mechanism comprises an electric motor driving system coupled to and for driving a steering wheel device wherein said servo system controls said electric motor to actuate said steering wheel to automatically compensate for said dead band.

33. The method as recited in claim 26 further comprising:

determining when a user is steering said vehicle; and

overriding said first and said second steering commands in response to said determining.

34. The method as recited in claim 25 wherein said position determining component comprises one or more of a ground based and a satellite based position determining component.

35. The method as recited in claim 34 wherein said satellite based position determining component comprises one or more of a global positioning system (GPS) system, a differential GPS system, a real-time kinematics (RTK) system, a networked RTK system, a GLONASS system, and a Galileo system.

36. The method as recited in claim 25 wherein said vehicle has application in one or more of agriculture, maintenance, construction, utility, and commerce.

37. A computer readable medium having computer usable code thereon for causing a computer system to perform a process for compensating for a dead band in the steering mechanism of a mobile machine, said process comprising:

measuring said dead band;

storing a value corresponding to said dead band; and

applying said dead band value to a controller of said steering mechanism wherein said steering mechanism is controlled according to said dead band value to compensate for said dead band.