SYSTEM AND METHOD FOR CONTROLLING POWER IN MACHINE HAVING HYDRAULIC AND ELECTRIC POWER SOURCES

• US 20120253610A1
• Filed: 04/01/2011
• Published: 10/04/2012
• Est. Priority Date: 04/01/2011
• Status: Abandoned Application

• Current Assignee: Caterpillar Incorporated
• Original Assignee: Caterpillar Incorporated
• Inventors: ANDERS, Jonathan W., Gorman, Corey L., Bernardi, John J.
• Application Number:
  US13/078,281
• Publication Number:
  US 20120253610A1
• Time in Patent Office: Days
• US Class Current: 701/50
• CPC Class Codes: B60K 6/12 by means of a chargeable fluidic accumulator
• CPC Class Codes: B60W 10/30 including control of auxiliary equipment, e.g. air-conditioning compressors or oil pumps
• CPC Class Codes: B60W 2300/17 Construction vehicles, e.g. graders, excavators
• CPC Class Codes: E02F 9/2091 Control of energy storage means for electrical energy, e.g. battery or capacitors energy recovery arrangements in hydraulic or pneumatic drives E02F9/2217
• CPC Class Codes: E02F 9/2095 Control of electric, electro-mechanical or mechanical equipment not otherwise provided for, e.g. ventilators, electro-driven fans control of hydraulic driven equipment E02F9/22
• CPC Class Codes: E02F 9/2221 Control of flow rate; Load sensing arrangements E02F9/2203 take precedence over E02F9/2221
• CPC Class Codes: Y02T 10/62 Hybrid vehicles

Abstract

A system for controlling power in a machine includes a controller configured to compare at least one of the following: a combined requested power level of a sum of a requested hydraulic power level and a requested electric power level to a combined maximum available power level, the requested hydraulic power level to a maximum available hydraulic power level, and the requested electric power level to a maximum available electric power level. If at least one of the maximum available power levels is less than the respective requested power level, the controller is configured to provide a signal for supplying electric power to the electric actuator at a level less than the requested electric power level, and a signal for supplying hydraulic power to the hydraulic actuator at a level less than the requested hydraulic power level.

Claims

1. A system for controlling power in a machine comprising an electric power source, a hydraulic power source, an electric actuator, and a hydraulic actuator, the system comprising:

a controller configured to;

receive a signal indicative of a requested hydraulic operation of the hydraulic actuator, the requested hydraulic operation corresponding to a requested hydraulic power level;

receive a signal indicative of a requested electric operation of the electric actuator, the requested electric operation corresponding to a requested electric power level; and

compare at least one of the following;

a combined requested power level of a sum of the requested hydraulic and electric power levels to a combined maximum available power level,

the requested hydraulic power level to a maximum available hydraulic power level, and

the requested electric power level to a maximum available electric power level,

wherein if at least one of the maximum available power levels is less than the respective requested power level;

provide a signal for supplying an amount of electric power to the electric actuator at a level less than the requested electric power level, and

provide a signal for supplying an amount of hydraulic power to the hydraulic actuator at a level less than the requested hydraulic power level.

2. The system of claim 1, wherein the maximum available hydraulic power level is based on either a predetermined maximum available hydraulic power level or a level of hydraulic power available from the hydraulic power source upon receipt of the signal indicative of the requested hydraulic operation.

3. The system of claim 1, wherein the maximum available electric power level is based on either a predetermined maximum available electric power level or a level of electric power available from the electric power source upon receipt of the signal indicative of the requested electric operation.

4. The system of claim 1, wherein the combined maximum available power level is based on either a predetermined combined maximum available power level or a level of combined power available from the hydraulic and electric power sources upon receipt of the signals indicative of the requested hydraulic and electric operation.

5. The system of claim 4, wherein the combined maximum available power level is based on a lesser of the predetermined combined maximum available power level and the level of combined power available from the hydraulic and electric power sources.

6. The system of claim 1, wherein the level less than the requested electric power level is based on a predetermined electric power output ratio associated with the electric actuator.

7. The system of claim 1, wherein the level less than the requested hydraulic power level is based on a predetermined hydraulic power output ratio associated with the hydraulic actuator.

8. The system of claim 1, wherein the machine includes a plurality of hydraulic actuators, and wherein the controller is configured to:

receive signals indicative of requested hydraulic operation of the plurality of hydraulic actuators, each requested hydraulic operation corresponding to a requested hydraulic power level for each of the hydraulic actuators;

sum the requested hydraulic power levels to determine a total requested hydraulic power level; and

compare the total requested hydraulic power level to the maximum available hydraulic power level, and if the maximum available hydraulic power level is less than the total requested hydraulic power level;

provide a signal for supplying an amount of electric power to the electric actuator at a level less than the requested electric power level, and

provide a signal for supplying an amount of hydraulic power to each of the plurality of hydraulic actuators at a level less than each of the respective requested hydraulic power levels.

9. The system of claim 8, wherein the level less than the requested electric power level is based on a predetermined electric power output ratio associated with the electric actuator.

10. The system of claim 8, wherein the level less than the requested hydraulic power level for each of the hydraulic actuators is based on respective predetermined hydraulic power output ratios associated with each of the hydraulic actuators.

11. A method for controlling power in a machine comprising an electric power source, a hydraulic power source, an electric actuator, and a hydraulic actuator, the method comprising:

receiving a signal indicative of a requested hydraulic operation of the hydraulic actuator, the requested hydraulic operation corresponding to a requested hydraulic power level;

receiving a signal indicative of a requested electric operation of the electric actuator, the requested electric operation corresponding to a requested electric power level; and

comparing at least one of the following;

a combined requested power level of a sum of the requested hydraulic and electric power levels to a combined maximum available power level,

the requested hydraulic power level to a maximum available hydraulic power level, and

the requested electric power level to a maximum available electric power level,

wherein if at least one of the maximum available power levels is less than the respective requested power level;

providing a signal for supplying an amount of electric power to the electric actuator at a level less than the requested electric power level, and

providing a signal for supplying an amount of hydraulic power to the hydraulic actuator at a level less than the requested hydraulic power level.

12. The method of claim 11, wherein the maximum available hydraulic power level is based on either a predetermined maximum available hydraulic power level or a level of hydraulic power available from the hydraulic power source upon receipt of the signal indicative of the requested hydraulic operation.

13. The method of claim 11, wherein the maximum available electric power level is based on either a predetermined maximum available electric power level or a level of electric power available from the electric power source upon receipt of the signal indicative of the requested electric operation.

14. The method of claim 11, wherein the combined maximum available power level is based on either a predetermined combined maximum available power level or a level of combined power available from the hydraulic and electric power sources upon receipt of the signals indicative of the requested hydraulic and electric operation.

15. The method of claim 14, wherein the combined maximum available power level is based on a lesser of the predetermined combined maximum available power level and the level of combined power available from the hydraulic and electric power sources.

16. The method of claim 11, wherein the level less than the requested electric power level is based on a predetermined electric power output ratio associated with the electric actuator.

17. The method of claim 11, wherein the level less than the requested hydraulic power level is based on a predetermined hydraulic power output ratio associated with the hydraulic actuator.

18. The method of claim 11, wherein the machine includes a plurality of hydraulic actuators, wherein the controller is configured to:

receive signals indicative of requested hydraulic operation of the plurality of hydraulic actuators, each requested hydraulic operation being associated with a requested hydraulic power level;

sum the requested hydraulic power levels to determine a total requested hydraulic power level; and

compare the total requested hydraulic power levels to the maximum available hydraulic power level, and if the maximum available hydraulic power level is less than the total requested hydraulic power level;

provide a signal for supplying an amount of electric power to the electric actuator at the level less than the requested electric power level, and

provide a signal for supplying an amount of hydraulic power to each of the plurality of hydraulic actuators at a level less than each of the respective requested hydraulic power levels.

19. The method of claim 18, wherein the level less than the requested electric power level is based on a predetermined electric power output ratio associated with the electric actuator.

20. The method of claim 18, wherein the level less than the requested hydraulic power level for each of the hydraulic actuators is based on respective predetermined hydraulic power output ratios associated with each of the hydraulic actuators.

21. A machine comprising:

a chassis;

an operator interface for controlling operation of the machine;

an electric power source coupled to the chassis;

a hydraulic power source coupled to the chassis;

an electric actuator coupled to the machine and in operative communication with the electric power source;

a hydraulic actuator coupled to the machine and in operative communication with the hydraulic power source; and

a controller configured to;

receive a signal from the operator interface indicative of a requested hydraulic operation of the hydraulic actuator, the requested hydraulic operation corresponding to a requested hydraulic power level;

receive a signal from the operator interface indicative of a requested electric operation of the electric actuator, the requested electric operation corresponding to a requested electric power level; and

compare at least one of the following;

a combined requested power level of a sum of the requested hydraulic and electric power levels to a combined maximum available power level,

the requested hydraulic power level to a maximum available hydraulic power level, and

the requested electric power level to a maximum available electric power level,

wherein if at least one of the maximum available power levels is less than the respective requested power level;

provide a signal for supplying an amount of electric power to the electric actuator at a level less than the requested electric power level, and

provide a signal for supplying an amount of hydraulic power to the hydraulic actuator at a level less than the requested hydraulic power level.

22. The machine of claim 21, wherein the electric power source includes at least one of a generator, a battery, and an ultra-capacitor.

23. The machine of claim 21, wherein the hydraulic power source includes at least one of a hydraulic pump and an accumulator.

24. The machine of claim 21, wherein the electric actuator includes an electric motor.

25. The machine of claim 21, wherein the hydraulic actuator includes at least one of a hydraulic motor and a hydraulic cylinder.

26. The machine of claim 21, wherein the machine further includes:

a cab rotatably mounted on the chassis;

a boom pivotally coupled to the cab; and

a stick pivotally coupled to the boom,

wherein the electric actuator includes an electric motor coupled to the cab and the chassis for rotating the cab with respect to the chassis,

wherein a first hydraulic actuator is coupled to the cab and the boom for pivotally moving the boom with respect to the cab, and

wherein a second hydraulic actuator is coupled to the boom and the stick for pivotally moving the stick with respect to the boom.

27. The machine of claim 26, further comprising an implement pivotally coupled to the stick, and a third hydraulic actuator coupled to the stick and the implement for pivotally moving the implement with respect to the stick.

28. The machine of claim 27, wherein the controller is configured to:

receive signals from the operator interface indicative of requested hydraulic operation of the first, second, and third hydraulic actuators, each of the requested hydraulic operations corresponding to a requested hydraulic power level for each of the first, second, and third hydraulic actuators;

sum the requested hydraulic power levels to determine a total requested hydraulic power level; and

compare the total requested hydraulic power level to the maximum available hydraulic power level, and if the maximum available hydraulic power level is less than the total requested hydraulic power level;

provide a signal for supplying an amount of electric power to the electric actuator at a level less than the requested electric power level, and

provide a signal for supplying an amount of hydraulic power to each of the first, second, and third hydraulic actuators at a level less than the each of the respective requested hydraulic power levels.

29. The machine of claim 28, wherein the level less than the requested electric power level is based on a predetermined electric power output ratio associated with the electric actuator.

30. The machine of claim 28, wherein the level less than the requested hydraulic power level for each of the first, second, and third hydraulic actuators is based on respective predetermined hydraulic power output ratios associated with each of the first and second hydraulic actuators.