Control strategy for reducing boom oscillation

Patent metadata

Field	Value
Publication number	US-10316929-B2
Application number	US-201415036749-A
Country	US
Kind code	B2
Filing date	Nov 7, 2014
Priority date	Nov 14, 2013
Publication date	Jun 11, 2019
Grant date	Jun 11, 2019

Abstract

A hydraulic system ( 600 ) and method for reducing boom dynamics of a boom ( 30 ), while providing counter-balance valve protection, includes a hydraulic cylinder ( 110 ), first and second counter-balance valves ( 300, 400 ), first and second control valves ( 700, 800 ), and first and second blocking valves ( 350, 450 ). A net load ( 90 ) is supported by a first chamber ( 116, 118 ) of the hydraulic cylinder, and a second chamber ( 118, 116 ) of the hydraulic cylinder may receive fluctuating hydraulic fluid flow from the second control valve to produce a vibratory response ( 950 ) that counters environmental vibrations ( 960 ) on the boom. The method may include measuring first pressure ripples at the second chamber and reducing a magnitude of second pressure ripples at the first chamber. The pressure ripples may be transformed into a flow command by multiplying the pressure ripples by a gain and/or phase shifting. The gain and/or the phase shifting may be adjusted by feedback. The feedback may include the second pressure ripples at the load holding chamber, a position of the hydraulic actuator, and/or an operator input. A reference signal may be filtered with a moving average filter.

First claim

What is claimed is:

1. A method of controlling vibration in a boom, the method comprising:
providing a hydraulic actuator including a first chamber and a second chamber;
selecting one of the first and the second chambers as a locked chamber;
selecting another of the first and the second chambers as an active chamber;
locking the locked chamber;
transferring a vibration canceling fluid flow to the active chamber; and
preventing hydraulic fluid from exiting the locked chamber with a first counter-balance valve in a closed configuration;
wherein the vibration canceling fluid flow is transferred to the active chamber via a second counter-balance valve in an open configuration.

2. The method of claim 1 , further comprising:
detecting which of the first and the second chambers is a load holding chamber;
wherein the load holding chamber is selected as the locked chamber; and
wherein the locked chamber prevents drifting of the hydraulic actuator.

3. The method of claim 2 , further comprising:
at least intermittently measuring a first pressure of the first chamber; and
at least intermittently measuring a second pressure of the second chamber;
wherein the load holding chamber is detected by comparing the first and the second pressures.

4. The method of claim 3 , further comprising:
providing a first pressure sensor at least intermittently fluidly connected to the first chamber; and
providing a second pressure sensor at least intermittently fluidly connected to the second chamber;
wherein the first pressure sensor measures the first pressure; and
wherein the second pressure sensor measures the second pressure.

5. The method of claim 4 , wherein the first pressure sensor is continuously fluidly connected to the first chamber and the second pressure sensor is continuously fluidly connected to the second chamber.

6. The method of claim 4 , wherein the first pressure sensor is at least intermittently fluidly connected to the first chamber via the first counter-balance valve and wherein the second pressure sensor is at least intermittently fluidly connected to the second chamber via the second counter-balance valve.

7. The method of claim 3 , further comprising:
providing a pressure sensor intermittently fluidly connected to the first chamber and intermittently fluidly connected to the second chamber, the pressure sensor intermittently measuring the first pressure and intermittently measuring the second pressure.

8. The method of claim 2 , further comprising:
measuring pressure ripples at the load holding chamber; and
reducing a magnitude of the pressure ripples by the transferring of the vibration canceling fluid flow to the active chamber.

9. The method of claim 2 , further comprising:
measuring first pressure ripples at the active chamber; and
reducing a magnitude of second pressure ripples at the load holding chamber by the transferring of the vibration canceling fluid flow to the active chamber.

10. The method of claim 9 , wherein the first pressure ripples at the active chamber are measured by a pressure sensor at a control valve adapted to pressurize and drain the active chamber, wherein a counter-balance valve is positioned between the control valve and the active chamber, and wherein the counter-balance valve is open when the first pressure ripples at the active chamber are measured by the pressure sensor at the control valve.

11. The method of claim 9 , wherein the measuring of the first pressure ripples at the active chamber and the transferring of the vibration canceling fluid flow to the active chamber are separated by time.

12. The method of claim 9 , further comprising:
transforming a shape of the first pressure ripples into a flow command that forms the vibration canceling fluid flow by:
multiplying the shape of the first pressure ripples by a gain; and
phase shifting the shape of the first pressure ripples.

13. The method of claim 12 , wherein the gain is a fixed gain and wherein the phase shifting is constant phase shifting.

14. The method of claim 12 , wherein the gain is a variable gain, wherein the phase shifting is variable phase shifting, and wherein at least one of the variable gain and the variable phase shifting is adjusted by feedback.

15. The method of claim 14 , wherein the feedback is the second pressure ripples at the load holding chamber.

16. The method of claim 14 , wherein the feedback is a position of the hydraulic actuator.

17. The method of claim 14 , wherein the feedback is an operator input.

18. The method of claim 2 , further comprising:
generating a reference signal starting prior to transferring the vibration canceling fluid flow to the active chamber;
deriving a variable from a characteristic measured from the hydraulic actuator;
summing the reference signal and the variable and thereby deriving a control variable; and
forming a flow characteristic of the vibration canceling fluid flow with the control variable.

19. The method of claim 18 , wherein the variable at least in part is derived from a pressure measured at the load holding chamber.

20. The method of claim 18 , further comprising:
filtering the reference signal with a moving average filter;
wherein the reference signal is generated from a first pressure measured at the first chamber and from a second pressure measured at the second chamber.

21. The method of claim 1 , further comprising:
providing a first control valve adapted to pressurize and drain the first chamber;
providing a second control valve adapted to pressurize and drain the second chamber;
pressurizing a pilot of the second counter-balance valve with the first control valve and thereby configuring the second counter-balance valve in the open configuration; and
generating the vibration canceling fluid flow with the second control valve.

22. The method of claim 21 , further comprising:
providing a first pressure sensor within a housing of the first control valve and thereby at least intermittently measuring a first pressure of the first chamber; and
providing a second pressure sensor within a housing of the second control valve and thereby at least intermittently measuring a second pressure of the second chamber.

23. The method of claim 1 , wherein the first chamber of the hydraulic actuator is a head chamber and the second chamber of the hydraulic actuator is a rod chamber.

24. The method of claim 1 , wherein the first chamber of the hydraulic actuator is a rod chamber and the second chamber of the hydraulic actuator is a head chamber.

Assignees

• Eaton Intelligent Power Ltd

Inventors

• Wang Meng (Rachel)
• Rannow Michael Berne

Classifications

• F15B2211/8613

  the abnormal condition being oscillations · CPC title

• F15B2211/35

  Directional control combined with flow control · CPC title

• F15B2211/3057

  having two valves, one for each port of a double-acting output member · CPC title

• E04G21/0454

  with boom vibration damper mechanisms · CPC title

• F15B2211/6306

  representing a pressure · CPC title