System and method for adjusting balance of operation of hydraulic and electric actuators

• US 9,067,501 B2
• Filed: 04/01/2011
• Issued: 06/30/2015
• Est. Priority Date: 04/01/2011
• Status: Active Grant

• Current Assignee: Caterpillar Incorporated
• Original Assignee: Caterpillar Incorporated
• Inventors: Anders, Jonathan W., Gorman, Corey L., Bernardi, John J.
• Primary Examiner(s): Tran, Khoi
• Assistant Examiner(s): Nguyen, Bao Long T
• Application Number:
  US13/078,295
• Publication Number:
  US 20120253570A1
• Time in Patent Office: 1,551 Days
• US Class Current: 1/1
• CPC Class Codes: B60L 15/2045 for optimising the use of energy
• CPC Class Codes: B60L 2200/40 Working vehicles
• CPC Class Codes: B60L 50/30 using propulsion power stored mechanically, e.g. in fly-wheels
• CPC Class Codes: Y02T 10/64 Electric machine technologies in electromobility
• CPC Class Codes: Y02T 10/70 Energy storage systems for electromobility, e.g. batteries
• CPC Class Codes: Y02T 10/72 Electric energy management in electromobility

Abstract

A system for controlling power in a machine includes an interface and a controller configured to receive a signal indicative of a requested hydraulic operation of a hydraulic actuator corresponding to a requested hydraulic power level. The controller is further configured to receive a signal indicative of a requested electric operation of the electric actuator corresponding to a requested electric power level. The controller is also configured to provide a signal for supplying electric power to the electric actuator less than the requested electric power level based on an electric power output ratio, and provide a signal for supplying hydraulic power to the hydraulic actuator less than the requested hydraulic power level based on a hydraulic power output ratio. At least one of the electric power output ratio and the hydraulic power output ratio is adjustable via the interface.

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:

an interface; and

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;

provide a signal for supplying an amount of electric power to the electric actuator at a level less than the requested electric power level based on an electric power output ratio; 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 based on a hydraulic power output ratio,

wherein at least one of the electric power output ratio and the hydraulic power output ratio is adjustable for the requested hydraulic and electric operations via the interface, and

wherein at least one of the electric power output ratio and the hydraulic power output ratio is adjustable within a predetermined range of ratios.

2. The system of claim 1, wherein the controller is configured provide the signal for supplying the amount of electric power to the electric actuator and the signal for supplying the amount of hydraulic power to the hydraulic actuator based on at least one of the following determinations:

a combined requested power level of a sum of the requested hydraulic and electric power levels is greater than a combined maximum available power level,

the requested hydraulic power level is greater than a maximum available hydraulic power level, and

the requested electric power level is greater than a maximum available electric power level.

3. The system of claim 2, wherein the respective maximum available power levels are based on either a predetermined maximum or a level of power available from the respective power sources upon receipt of the signals indicative of the requested hydraulic and electric operation.

4. The system of claim 3, wherein the respective maximum available power levels are based on a lesser of the predetermined maximum and the level of power available from the respective power sources.

5. 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 and the requested electric power level to determine a total requested power level;

provide a signal for supplying an amount of electric power to the electric actuator at a level based on the electric power output ratio; and

provide a signal for supplying an amount of hydraulic power to each of the plurality of hydraulic actuators at a level based on respective hydraulic power output ratios associated with each of the respective hydraulic actuators,

wherein at least one of the respective hydraulic power output ratios is adjustable via the interface.

6. The system of claim 5, wherein the controller is configured to store a selected combination of the electric power output ratio and the hydraulic power output ratios.

7. A method executable by a processor of operating a hydraulic actuator and an electric 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;

providing a signal for supplying an amount of electric power to the electric actuator at a level less than the requested electric power level based on an electric power output ratio;

providing a signal for supplying an amount of hydraulic power to the hydraulic actuator at a level less than the requested hydraulic power level based on a hydraulic power output ratio; and

adjusting at least one of the electric power output ratio and the hydraulic power output ratio for the requested hydraulic and electric operations via an interface,

wherein adjusting at least one of the electric power output ratio and the hydraulic power output ratio comprises adjusting the at least one of the electric power output ratio and the hydraulic power output ratio within a predetermined range of ratios.

8. The method of claim 7, wherein providing the signal for supplying the amount of electric power to the electric actuator and the signal for supplying the amount of hydraulic power to the hydraulic actuator based on at least one of the following determinations:

a combined requested power level of a sum of the requested hydraulic and electric power levels is greater than a combined maximum available power level,

the requested hydraulic power level is greater than a maximum available hydraulic power level, and

the requested electric power level is greater than a maximum available electric power level.

9. The method of claim 8, wherein the respective maximum available power levels are based on either a predetermined maximum or a level of power available from the respective power sources upon receipt of the signal indicative of the requested hydraulic and electric operation.

10. The method of claim 9, wherein the respective maximum available power levels are based on a lesser of the predetermined maximum and the level of power available from the respective power sources.

11. The method of claim 7, further including:

receiving signals indicative of requested hydraulic operations of a plurality of hydraulic actuators, each requested hydraulic operation being associated with a respective requested hydraulic power level;

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

providing respective signals for supplying an amount of hydraulic power to each of the plurality of hydraulic actuators at a level based on respective hydraulic power output ratios associated with each of the respective hydraulic actuators,

wherein at least one of the respective hydraulic power output ratios is adjustable via the interface.

12. The method of claim 11, further including storing a selected combination of the electric power output ratio and the hydraulic power output ratios.

13. A machine comprising:

a chassis;

an interface;

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 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;

provide a signal for supplying an amount of electric power to the electric actuator at a level less than the requested electric power level based on an electric power output ratio; 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 based on a hydraulic power output ratio,

wherein at least one of the electric power output ratio and the hydraulic power output ratio is adjustable for the requested hydraulic and electric operations via the interface, and

wherein at least one of the electric power output ratio and the hydraulic power output ratio is adjustable within a predetermined range of ratios.

14. The machine of claim 13, wherein the electric power source includes at least one of a generator, a battery, and an ultra-capacitor.

15. The machine of claim 13, wherein the hydraulic power source includes at least one of a hydraulic pump and an accumulator.

16. The machine of claim 13, wherein the electric actuator includes an electric motor.

17. The machine of claim 13, wherein the hydraulic actuator includes at least one of a hydraulic motor and a hydraulic cylinder.

18. The machine of claim 13, 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.

19. The machine of claim 18, 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.

20. The machine of claim 19, wherein the controller is configured to:

receive signals from the 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

provide signals for supplying an amount of hydraulic power to each of the first, second, and third hydraulic actuators at a level based on respective hydraulic power output ratios;

wherein the respective hydraulic power output ratios are adjustable via the interface.

21. The machine of claim 20, wherein the controller is configured to store a selected combination of the electric power output ratio and the hydraulic power output ratios.

22. The machine of claim 13, wherein at least one of the electric power output ratio and the hydraulic power output ratio is adjustable within a predetermined range of ratios.