Torque load control system and method

• US 20090319136A1
• Filed: 06/20/2008
• Published: 12/24/2009
• Est. Priority Date: 06/20/2008
• Status: Active Grant

• Current Assignee: Caterpillar Incorporated
• Original Assignee: Caterpillar Incorporated
• Inventors: Anderson, Randall T., Gorman, Corey L.
• Granted Patent: US 8,793,002 B2
• Time in Patent Office: Days
• US Class Current: 701/54
• CPC Class Codes: B60W 50/06 Improving the dynamic response of the control system, e.g. improving the speed of regulation or avoiding hunting or overshoot
• CPC Class Codes: E02F 9/2246 Control of prime movers, e.g. depending on the hydraulic load of work tools
• CPC Class Codes: F02D 2250/26 by applying a torque limit
• CPC Class Codes: F02D 41/021 Introducing corrections for particular conditions exterior to the engine conjoint control of vehicle sub-units for propelling the vehicle B60W30/18
• CPC Class Codes: F02D 41/1497 With detection of the mechanical response of the engine

Abstract

A machine may include a torque producing system, and a torque consuming device including load controls operable to generate a request for torque. The machine may also include a control system coupled to the torque producing system and the load controls. The control system may be operable to receive the request for torque, determine a torque limit based on the requested torque, and communicate the torque limit to the load controls, the load controls being operable to adjust operation of the torque consuming device based on the torque limit.

Claims

1. A machine comprising:

a torque producing system;

a torque consuming device including load controls operable to generate a request for torque; and

a control system coupled to the torque producing system and the load controls, operable to

receive the request for torque,

determine a torque limit based on the requested torque, and

communicate the torque limit to the load controls, the load controls being operable to adjust operation of the torque consuming device based on the torque limit.

2. The machine of claim 1, wherein the torque consuming device is operable to exert a torque load on the torque producing system.

3. The machine of claim 2, wherein the torque limit sets a limit on the torque load that the torque consuming device exerts on the torque producing system.

4. The machine of claim 2, wherein when the torque load is less than or equal to the torque limit, a speed of the torque producing system is greater than or equal to a target speed.

5. The machine of claim 4, wherein the target speed is at or above an underspeed set point of the torque producing system.

6. A machine comprising:

a torque producing system;

one or more torque consuming devices capable of consuming torque in excess of a rated capacity of the torque producing system; and

a control system coupled to the torque producing system and the one or more torque consuming devices, the control system including a torque load control operable to limit operation of the one or more torque consuming devices to prevent exceeding of the rated capacity of the torque producing system.

7. The machine of claim 6, wherein the torque producing system has an actual operating capacity, and the rated capacity is less than or equal to the actual operating capacity.

8. The machine of claim 6, wherein the rated capacity is indicative of a torque producing capability of the torque producing system.

9. The machine of claim 6, wherein the torque load control is configured to limit torque consumption to a torque limit.

10. The machine of claim 9, wherein when torque consumption is less than or equal to the torque limit, a speed of the torque producing system is greater than or equal to a target speed.

11. A machine comprising:

a torque producing system operable within a range of operating speeds;

a torque consuming device operable to generate a signal requesting torque from the torque producing system; and

a control system coupled to the torque producing system and the torque consuming device, operable to maintain the torque producing system at a target operating speed as the torque requested varies by controlling torque consumed by the torque consuming device based on the torque requested and one or more additional machine operating parameters.

12. The machine of claim 11, wherein the target operating speed is variable.

13. The machine of claim 11, wherein the target operating speed is a steady state speed.

14. The machine of claim 11, wherein the target operating speed is at or above an underspeed set point of the torque producing system, the torque producing system being susceptible to stalling when the torque producing system operates below the underspeed set point.

15. The machine of claim 11, wherein the control system is operable to determine a torque limit, and limit the torque consumed to the torque limit.

16. A machine comprising:

a torque producing system;

one or more torque consuming devices operable to exert a torque load on the torque producing system;

a control system coupled to the torque producing system and the one or more torque consuming devices, the control system including

a torque error estimator, and

one or more electronic devices operable to sense operating conditions of the torque producing system and the one or more torque consuming devices, and provide torque data to the control system based on the sensed operating conditions, the torque error estimator being operable to compensate for error in the torque data.

17. The machine of claim 16, wherein the error is at least partially caused by inaccuracy of the one or more electronic devices.

18. The machine of claim 17, wherein the error is at least partially caused by the one or more electronic devices being incapable of sensing the operating conditions of an additional torque consuming device.

19. The machine of claim 17, wherein the control system is operable to calculate a torque load limit with the torque data.

20. An electronic control module including instructions for performing a method, the method comprising:

obtaining input signals related to at least one of a torque producing system and a torque consuming device;

calculating an initial error value indicative of error associated with at least one of the torque producing system and the torque consuming device based on the input signals;

subtracting a feedback value from the initial error value to calculate a modified error value; and

adjusting the modified error value to produce an adjusted error value used to control operation of at least one of the torque producing system and the torque consuming device.

21. The electronic control module of claim 20, wherein the adjusted error value becomes a new feedback value.

22. The electronic control module of claim 20, wherein the adjusted error value is used to adjust a torque load limit for the torque producing system.

23. The electronic control module of claim 20, wherein the input signals include torque data for at least one of the torque producing system and the torque consuming device.

24. The electronic control module of claim 20, wherein the adjusted error value is used to set a limit on a torque load exerted by the torque consuming device on the torque producing system.

25. A method for machine modification, comprising:

modifying a machine that includes a torque producing system to include

a torque consuming device coupled to controls operable to provide a torque request signal based on operating parameters of the torque consuming device, and

a torque load control configured to determine a torque load limit for the torque producing system, the machine being operable to operate at least one of the torque producing system and the torque consuming device based on the torque load limit and the torque request signal.

26. The method of claim 25, wherein modifying the machine includes replacing a component of the machine with the torque consuming device.

27. The method of claim 25, wherein modifying the machine includes adding the torque consuming device to the machine.

28. The method of claim 25, wherein the torque consuming device is operable to exert a torque load on the torque producing system.

29. The method of claim 25, wherein operating at least one of the torque producing system and the torque consuming device includes maintaining the torque load at or below the torque load limit.

30. The method of claim 25, wherein the controls are operable to provide a torque consumption signal indicative of the torque consumed by the torque consuming device.

31. The method of claim 30, wherein the controls are operable to limit the torque consumed by the torque consuming device in response to the torque load limit.

32. The method of claim 25, further including modifying the machine to include torque producing system controls operable to provide input signals used by torque load control to determine the torque load limit.

33. A method for modifying a machine including a torque producing system, and a torque consuming device coupled to controls operable to provide a torque request signal, the method of machine modification comprising:

modifying a control system of the machine to

include a torque load control operable to determine a torque load limit for the torque producing system, and

control an operation of at least one of the torque producing system and the torque consuming device based on the torque load limit and the torque request signal.

34. The method of claim 33, wherein including the torque load control includes adding the torque load control to the control system.

35. The method of claim 33, further including modifying the control system to include a torque error estimator operable to adjust the torque load limit to compensate for error.

36. The method of claim 33, wherein controlling the operation includes maintaining a torque load exerted by the torque consuming device on the torque producing system at or below the torque load limit.

37. The method of claim 33, wherein modifying the control system includes replacing a component of the control system with the torque load control.

38. A machine comprising:

a torque producing system;

torque consuming devices operable to exert a torque load on the torque producing system;

a control system operable to determine a torque load limit for the torque producing system, the control system being

in communication with the torque producing system,

communicatively linked to one or more first torque consuming devices,

uncommunicative with one or more second torque consuming devices, and

operable to calculate torque consumed by the one or more first torque consuming devices based at least in part on communications from the one or more first torque consuming devices, and calculate torque consumed by the one or more second torque consuming devices based on sensed operating conditions of the machine.

39. The machine of claim 38, wherein the control system is operable to take into account the torque consumed by the one or more first torque consuming devices, and the torque consumed by the one or more second torque consuming devices, to determine the torque load limit.

40. The machine of claim 38, wherein the control system is operable to maintain the torque load at or below the torque load limit.

41. The machine of claim 38, wherein the control system is communicatively linked to the one or more first torque consuming devices by one or more sensors operable to sense operating conditions of the one or more first torque consuming devices.

42. An electronic control module including instructions for performing a method, the method comprising:

determining an amount of available torque currently available from a torque producing system;

determining a torque load limit for the torque producing system based on the determined amount of available torque currently available and an operating speed of the torque producing system, including determining the torque load limit in a manner to prevent the operating speed from decaying at a rate greater than a target deceleration rate; and

controlling one or more torque consuming devices that receive torque from the torque producing system based on the torque load limit.

43. The electronic control module of claim 42, wherein determining the torque load limit includes determining a difference between the operating speed and an underspeed set point of the torque producing system.

44. The electronic control module of claim 43, wherein determining the torque load limit includes determining an inertial torque based on the difference between the operating speed and the underspeed set point.

45. The electronic control module of claim 44, wherein determining the torque load limit includes adjusting the torque load limit based on the inertial torque.

46. The electronic control module of claim 45, wherein determining the torque load limit includes limiting the inertial torque to a target range to prevent the operating speed from decaying at a rate greater than the target deceleration rate.