MULTI-MODE SKID STEERING

• US 20070040341A1
• Filed: 09/08/2006
• Published: 02/22/2007
• Est. Priority Date: 02/21/2003
• Status: Active Grant

• Current Assignee: Lockheed Martin Corporation (Martin Marietta Corporation)
• Original Assignee: Lockheed Martin Corporation (Martin Marietta Corporation)
• Inventors: Kaloust, Joseph, Chun, Wendell
• Granted Patent: US 8,839,891 B2
• Time in Patent Office: Days
• US Class Current: 280/5.509
• CPC Class Codes: B60G 17/0162 mainly during a motion involving steering operation, e.g. cornering, overtaking B60G17/0164 takes precedence
• CPC Class Codes: B60G 2300/07 Off-road vehicles
• CPC Class Codes: B62D 1/283 for unmanned vehicles
• CPC Class Codes: B62D 11/001 control systems B62D11/183 takes precedence
• CPC Class Codes: B62D 11/003 Electric or electronic control systems
• CPC Class Codes: B62D 6/00 Arrangements for automatically controlling steering depending on driving conditions sensed and responded to, e.g. control circuits means for initiating a change in direction B62D1/00; steering valves B62D5/06; combined with means for inclining the vehicle body or wheels on bends B62D9/00
• CPC Class Codes: B62D 61/10 with more than four wheels tractors of the low ground pressure type B62D49/002
• CPC Class Codes: B62D 61/12 with variable number of ground engaging wheels, e.g. with some wheels arranged higher than others, or with retractable wheels for manoeuvring purposes only B60S

Abstract

A method includes operating a wheeled vehicle including an articulated suspension system; and articulating the suspension system to skid steer the vehicle. A wheeled vehicle having an articulated suspension system includes a skid steering controller capable of articulating the suspension system to skid steer the vehicle. The skid steering controller may be implemented in software and may, but does not necessarily, include three stages for applying a differential torque, varying the traction of at least one wheel, and finely adjusting the wheel'"'"'s suspension to approach a critical damped response of the vehicle turning rate with respect to its commanded rate, respectively.

Claims

1. A method, comprising:

operating a wheeled vehicle including an articulated suspension system; and

articulating the suspension system to skid steer the vehicle.

2. The method of claim 1, further comprising applying a differential torque to each of two sides of the vehicle to skid steer the vehicle.

3. The method of claim 1, wherein articulating the suspension system includes varying the traction of at least one wheel responsive to a turn command.

4. The method of claim 1, wherein articulating the suspension system includes performing a coarse articulation.

5. The method of claim 4, wherein articulating the suspension system includes performing a fine articulation.

6. The method of claim 1, wherein articulating the suspension system includes performing a fine articulation.

7. The method of claim 1, wherein articulating the suspension system further includes articulating the suspension system to approach a critical damped response of the vehicle turning rate with respect to a commanded rate.

8. A skid steering controller, comprising:

a processor;

a bus system;

a storage communicating with the processor over the bus system;

a software application residing on the storage that, when invoked by the processor, is capable of articulating a suspension system of a vehicle to skid steer the vehicle.

9. The skid steering controller of claim 8, wherein the software application is further capable of applying a differential torque to each of two sides of the vehicle to skid steer the vehicle.

10. The skid steering controller of claim 8, wherein articulating the suspension system includes varying the traction of at least one wheel responsive to a turn command.

11. The skid steering controller of claim 8, wherein articulating the suspension system includes performing a coarse articulation.

12. The skid steering controller of claim 8, wherein articulating the suspension system includes performing a fine articulation.

13. The skid steering controller of claim 8, wherein articulating the suspension system further includes articulating the suspension system to approach a critical damped response of the vehicle turning rate with respect to a commanded rate.

14. A program storage medium encoded with instructions that, when executed by a computing device, perform a method comprising articulating a suspension system of a vehicle to skid steer the vehicle.

15. The program storage medium of claim 14, wherein the method further comprises applying a differential torque to each of two sides of the vehicle to skid steer the vehicle.

16. The program storage medium of claim 14, wherein articulating the suspension system includes varying the traction of at least one wheel responsive to a turn command.

17. The program storage medium of claim 14, wherein articulating the suspension system includes performing a coarse articulation.

18. The program storage medium of claim 14, wherein articulating the suspension system includes performing a fine articulation.

19. The program storage medium of claim 14, wherein articulating the suspension system further includes articulating the suspension system to approach a critical damped response of the vehicle turning rate with respect to a commanded rate.

20. A vehicle, comprising:

a plurality of wheels;

an articulated suspension system by which the wheels are mounted to the vehicle; and

a skid steering controller capable of articulating the suspension system to skid steer the vehicle.

21. The vehicle of claim 20, wherein the skid steering controller is further capable of applying a differential torque to each of two sides of the vehicle to skid steer the vehicle.

22. The vehicle of claim 20, wherein articulating the suspension system includes varying the traction of at least one wheel responsive to a turn command.

23. The vehicle of claim 20, wherein articulating the suspension system includes performing a coarse articulation.

24. The vehicle of claim 20, wherein articulating the suspension system includes performing a fine articulation.

25. The vehicle of claim 20, wherein articulating the suspension system further includes articulating the suspension system to approach a critical damped response of the vehicle turning rate with respect to a commanded rate.

26. A method for skid steering, comprising:

applying a differential torque to each of two sides of a wheeled vehicle including an articulated suspension system;

articulating at least one wheel assembly to vary the traction of at least one wheel and affect the turning capability of the vehicle; and

modifying the articulation to approach a critical damped response of the vehicle turning rate with respect to a commanded rate

27. The method of claim 26, wherein applying the differential torque includes at least one of braking one side of the wheeled vehicle, accelerating one side of the vehicle, and rotating the wheels on the two sides in different directions.

28. The method of claim 26, wherein articulating the wheel assembly includes rotationally articulating the wheel assembly.

29. The method of claim 26, wherein articulating the wheel assembly includes linearly articulating the wheel assembly.

30. The method of claim 26, wherein:

articulating the wheel assembly includes performing a coarse articulation; and

modifying the articulation includes performing a fine articulation.

31. A computer-implemented method for use in a wheeled vehicle including an articulated suspension system, comprising:

receiving a turn command; and

articulating the suspension system to skid steer the vehicle responsive to the turn command.

32. The computer-implemented method of claim 31, further comprising applying a differential torque to each of two sides of the vehicle to skid steer the vehicle.

33. The computer-implemented method of claim 31, wherein articulating the suspension system includes varying the traction of at least one wheel responsive to a turn command.

34. The computer-implemented method of claim 31, wherein articulating the suspension system includes performing a coarse articulation.

35. The computer-implemented method of claim 31, wherein articulating the suspension system includes performing a fine articulation.

36. The computer-implemented method of claim 31, wherein articulating the suspension system further includes articulating the suspension system to approach a critical damped response of the vehicle turning rate with respect to a commanded rate.

37. A skid steer controller, comprising:

a first stage capable of applying a differential torque to each side of a vehicle;

a second stage capable of varying the traction of at least one wheel contacting the ground surface; and

a third stage capable of finely adjusting the wheel'"'"'s suspension to approach a critical damped response of the vehicle turning rate with respect to its commanded rate.

38. The skid steer controller of claim 37, wherein applying the differential torque includes at least one of braking one side of the wheeled vehicle, accelerating one side of the vehicle, and rotating the wheels on the two sides in different directions.

39. The method of claim 37, wherein articulating the wheel assembly includes rotationally articulating the wheel assembly.

40. The method of claim 37, wherein articulating the wheel assembly includes linearly articulating the wheel assembly.

41. The method of claim 37, wherein:

articulating the wheel assembly includes performing a coarse articulation; and

modifying the articulation includes performing a fine articulation.

42. A method for skid steering a wheeled vehicle having an articulable suspension system comprising skid-steering the vehicle in multiple modes.

43. The method of claim 42, wherein at least one of the modes includes articulating at least one wheel assembly to vary the traction of the wheel and affect the turning capability of the vehicle.

44. The method of claim 43, wherein articulating the wheel assembly includes rotationally articulating the wheel assembly.

45. The method of claim 43, wherein articulating the wheel assembly includes linearly articulating the wheel assembly.

46. The method of claim 43, wherein:

articulating the wheel assembly includes performing a coarse articulation; and

modifying the articulation includes performing a fine articulation.

47. The method of claim 42, wherein the multiple modes include at least one of:

performing a coarse articulation; and

performing a fine articulation.

48. The method of claim 42, wherein the multiple modes include applying a differential torque to each of two sides of the vehicle to skid steer the vehicle.