Mobile-machine navigation system

• US 20070162219A1
• Filed: 01/06/2006
• Published: 07/12/2007
• Est. Priority Date: 01/06/2006
• Status: Active Grant

• Current Assignee: Caterpillar Incorporated
• Original Assignee: Caterpillar Incorporated
• Inventors: Stoller, Jason, Inoue, Makoto
• Granted Patent: US 7,596,451 B2
• Time in Patent Office: Days
• US Class Current: 701/200
• CPC Class Codes: B62D 1/28 non-mechanical , e.g. following a line or other known markers
• CPC Class Codes: G05D 1/0278 using satellite positioning signals, e.g. GPS

Abstract

A method of navigating a mobile machine dependent upon the relationship of the mobile machine to a target path includes operating a steering system to change the heading of the mobile machine in response to the mobile machine deviating from a first navigational dead band. Additionally, the method may include subsequently operating the steering system to make a heading change of the mobile machine only in response to predetermined events, which may include operating the steering system to make a heading change of the mobile machine if the mobile machine deviates from a second navigational dead band.

Claims

1. A method of navigating a mobile machine dependent upon a relationship of the mobile machine to a target path, the method comprising:

in response to the mobile machine deviating from a first navigational dead band, operating a steering system to change the heading of the mobile machine; and

subsequently, operating the steering system to make a heading change of the mobile machine only in response to predetermined events, including operating the steering system to make a heading change of the mobile machine if the mobile machine deviates from a second navigational dead band.

2. The method of claim 1, wherein the first navigational dead band is a range of positions including the target path.

3. The method of claim 1, wherein operating the steering system to make a heading change in response to the mobile machine deviating from the first navigational dead band includes operating the steering system to direct the mobile machine toward the target path.

4. The method of claim 1, wherein operating the steering system to make a heading change only in response to predetermined events further includes operating the steering system to change the heading of the mobile machine in response to the mobile machine reaching a target zone, the target zone including the target path.

5. The method of claim 4, further including:

subsequent to operating the steering system to change the heading of the mobile machine in response to the mobile machine reaching the target zone, operating the steering system to make a heading change only if the mobile machine again deviates from the first navigational dead band.

6. The method of claim 4, wherein the target zone includes only the target path.

7. The method of claim 1, further including:

as the mobile machine moves, repeatedly defining a look-ahead point on the target path ahead of a point on the target path nearest the mobile machine; and

wherein operating the steering system to make a heading change in response to the mobile machine deviating from the first navigational dead band includes operating the steering system to direct the mobile machine toward the look-ahead point.

8. The method of claim 1, further including:

as the mobile machine moves, repeatedly defining a look-ahead point on the target path ahead of a point on the target path nearest the mobile machine; and

wherein operating the steering system to make a heading change in response to the mobile machine deviating from the second navigational dead band includes operating the steering system to direct the mobile machine toward the look-ahead point.

9. The method of claim 1, wherein operating the steering system to make heading changes includes operating the steering system to induce a speed differential between a first propulsion device of the mobile machine and a second propulsion device of the mobile machine.

10. The method of claim 1, wherein operating the steering system to make heading changes includes operating the steering system to induce a speed differential between a first propulsion device of the mobile machine and a second propulsion device of the mobile machine at least partially by modulating at least one clutch or brake.

11. The method of claim 1, wherein:

the second navigational dead band includes a range of headings; and

operating the steering system to make a heading change in response to the mobile machine deviating from the second navigational dead band includes operating the steering system to make a heading change when the heading of the mobile machine deviates from the range of headings.

12. The method of claim 11, further including:

subsequent to making the heading change in response to the mobile machine deviating from the first navigational dead band, repeatedly

redefining a target heading of the mobile machine; and

redefining the range of headings as a function of the target heading.

13. A mobile-machine navigation system for navigating a mobile machine, the mobile-machine navigation system comprising:

navigation controls, including a steering system operable to adjust the heading of the mobile machine;

the navigation controls being configured to execute a method of navigating the mobile machine dependent upon the relationship of the mobile machine to a target path, the method of navigating the mobile machine including

operating in a first mode until the mobile machine deviates from a first navigational dead band;

in response to the mobile machine deviating from the first navigational dead band, operating the steering system to change the heading of the mobile machine and, subsequently, operating in a second mode until the mobile machine reaches a target zone, the target zone including the target path; and

in response to the mobile machine reaching the target zone, operating the steering system to make a heading change and, subsequently, returning to operation in the first mode.

14. The mobile-machine navigation system of claim 13, wherein operating in the second mode includes operating the steering system to make a heading change only in response to the mobile machine deviating from a second navigational dead band and in response to the mobile machine reaching the target zone.

15. The mobile-machine navigation system of claim 14, wherein the second navigational dead band is a range of headings.

16. The mobile-machine navigation system of claim 13, wherein operating in the first mode includes allowing the mobile machine to travel without operating the steering system to make a heading change.

17. The mobile-machine navigation system of claim 16, wherein the method of navigating the mobile machine further includes:

as the mobile machine travels, repeatedly redefining a look-ahead point on the target path ahead of a point on the target path nearest the mobile machine;

wherein operating in the first mode includes defining the look-ahead point in a first manner; and

wherein operating in the second mode includes defining the look-ahead point in a second manner.

18. The mobile-machine navigation system of claim 13, wherein the target zone includes only the target path.

19. A method of navigating a mobile machine dependent upon the relationship of the mobile machine to a target path and a first navigational dead band defined as a function of the target path, the method comprising:

in response to each deviation of the mobile machine from the first navigational dead band, operating a steering system to make a heading change to direct the mobile machine toward a portion of the target path ahead of a point on the target path nearest the mobile machine.

20. The method of claim 19, further including:

as the mobile machine travels, repeatedly defining a look-ahead point on the target path ahead of the point on the target path nearest the mobile machine;

wherein operating the steering system to make a heading change in response to each deviation of the mobile machine from the first navigational dead band includes operating the steering system to redirect the mobile machine toward the look-ahead point.

21. The method of claim 20, wherein defining the look-ahead point includes determining a look-ahead distance as a function of the speed of the mobile machine and defining the look-ahead point as a point on the target path ahead of the point on target path nearest the mobile machine by the look-ahead distance.

22. The method of claim 19, further including:

subsequent to making a heading change in response to the mobile machine deviating from the first navigational dead band, the next time the mobile machine reaches a target zone that includes the target path, operating the steering system to make a heading change toward a portion of the target path ahead of a point on the target path nearest the mobile machine.

23. The method of claim 22, further including:

between making the heading change in response to the mobile machine deviating from the first navigational dead band and making the heading change in response to reaching the target zone, operating the steering system to make a heading change only in response to the mobile machine deviating from a second navigational dead band.

24. The method of claim 22, further including:

subsequent to making the heading change in response to the mobile machine reaching the target zone, allowing the mobile machine to travel without operating the steering system to make a heading change until the mobile machine again deviates from the first navigational dead band.

25. The method of claim 22, wherein the target zone includes only the target path.

26. The method of claim 19, wherein the first navigational dead band is a range of positions including the target path.

27. The method of claim 19, wherein operating the steering system to change the heading of the mobile machine includes modulating at least one clutch or brake.

28. A mobile-machine navigation system for navigating a mobile machine, the mobile-machine navigation system comprising:

navigation controls, the navigation controls including a steering system; and

the navigation controls being configured to execute a method of navigating the mobile machine dependent upon a relationship of the mobile machine to a target path and a target zone that includes the target path, the method of navigating the mobile machine including

in response to the mobile machine moving from off the target zone onto the target zone, operating the steering system to make a heading change toward a portion of the target path ahead of a point on the target path nearest the mobile machine.

29. The mobile-machine navigation system of claim 28, wherein the method of navigating the mobile machine further includes:

subsequent to operating the steering system to make a heading change in response to the mobile machine moving onto the target zone, allowing the mobile machine to travel without operating the steering system to make heading changes until the mobile machine deviates from a navigational dead band that includes the target path.

30. The mobile-machine navigation system of claim 28, wherein:

the method of navigating the mobile machine further includes repeatedly defining a look-ahead point on the target path ahead of the point on the target path nearest the mobile machine; and

operating the steering system to make a heading change in response to the mobile machine moving onto the target zone includes operating the steering system to direct the mobile machine toward the look-ahead point.

31. The mobile-machine navigation system of claim 28, wherein the method of navigating the mobile machine further includes:

prior to making the heading change in response to the mobile machine moving onto the target zone, in response to the mobile machine deviating from a first navigational dead band, operating the steering system to make a heading change toward a portion of the target path ahead of a point on the target path nearest the mobile machine.

32. The mobile-machine navigation system of claim 31, wherein the method of navigating the mobile machine further includes:

between making the heading change in response to the mobile machine deviating from the first navigational dead band and making the heading change in response to the mobile machine moving onto the target zone, operating the steering system to make a heading change only in response to the mobile machine deviating from a second navigational dead band.

33. The mobile-machine navigation system of claim 31, wherein the first navigational dead band is a range of positions including the target path.

34. The mobile-machine navigation system of claim 28, wherein:

the propulsion system includes a first propulsion device and a second propulsion device; and

the steering system is configured to effect heading changes of the mobile machine by inducing a speed differential between the first propulsion device and the second propulsion device.

35. The mobile-machine navigation system of claim 28, wherein the target zone includes only the target path.

36. The mobile-machine navigation system of claim 28, wherein:

the propulsion system includes a first propulsion device and a second propulsion device; and

the steering system is configured to effect heading changes of the mobile machine by inducing a speed differential between the first propulsion device and the second propulsion device at least partially by modulating at least one clutch or brake.