Methods and apparatus to enable boom bounce reduction and prevent un-commanded motion in hydraulic systems

Patent metadata

Field	Value
Publication number	US-10323663-B2
Application number	US-201515326395-A
Country	US
Kind code	B2
Filing date	Jul 15, 2015
Priority date	Jul 15, 2014
Publication date	Jun 18, 2019
Grant date	Jun 18, 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 actuator ( 110 ), first and second counter-balance valves ( 300, 400 ), first and second independent control valves ( 700, 800 ), and first and second blocking valves ( 350, 450 ). The actuator includes first and second corresponding chambers. In a first mode, the second counter-balance valve is opened by the first control valve, and the first counter-balance valve is opened by the second control valve. In a second mode, at least one of the counter-balance valves is closed. A meter-out control valve ( 800, 700 ) may be operated in a flow control mode, and/or a meter-in control valve ( 700, 800 ) may be operated in a pressure control mode. Boom dynamics reduction may occur while the boom is in motion (e.g., about a worksite). By opening the counter-balance valves, sensors at the control valves may be used to characterize external loads. The control valves may respond to the external loads and at least partially cancel unwanted boom dynamics. The system may further detecting faults in actuators with counter-balance valves and prevent any single point fault from causing a boom falling event and/or mitigate such faults.

First claim

What is claimed is:

1. A method of controlling a hydraulic actuator hydraulically coupled to a pair of counter-balance valves, the method comprising:
providing the hydraulic actuator, the hydraulic actuator including a pair of chambers hydraulically coupled to the pair of counter-balance valves;
providing a pair of control valves hydraulically coupled to the pair of counter-balance valves;
operating a first control valve of the pair of control valves in a pressure control mode;
operating a second control valve of the pair of control valves in a flow control mode; and
transferring hydraulic fluid flow with the pair of control valves to/from the hydraulic actuator via the pair of counter-balance valves,
wherein at least one of the pair of chambers is a load holding chamber, and wherein a vibratory cancelation flow of hydraulic fluid is transferred to the load holding chamber.

2. The method of claim 1 , further comprising pressurizing a second pilot of a second counter-balance valve of the pair of counter-balance valves with the first control valve and thereby opening the second counter-balance valve.

3. The method of claim 2 , further comprising pressurizing a first pilot of a first counter-balance valve of the pair of counter-balance valves with the second control valve and thereby opening the first counter-balance valve.

4. The method of claim 2 , further comprising:
testing for a fault condition of the second control valve; and
indicating a valve fault if the fault condition is present.

5. The method of claim 4 , further comprising:
regulating an output pressure from the first control valve if the valve fault is indicated and if a lower-override command is indicated;
regulating a pilot pressure that is pressurizing the second pilot of the second counter-balance valve by the regulating of the output pressure from the first control valve; and
throttling the second counter-balance valve by the regulating of the pilot pressure and thereby lowering an apparatus actuated by the hydraulic actuator.

6. The method of claim 4 , further comprising closing the second counter-balance valve by depressurizing the second pilot of the second counter-balance valve with the first control valve if the valve fault is indicated and thereby stopping motion of the hydraulic actuator.

7. The method of claim 4 , wherein the testing for the fault condition of the second control valve includes monitoring a position of a spool of the second control valve and comparing the position of the spool with a spool position command transmitted by a controller to the second control valve and wherein the indicating of the valve fault occurs if the position of the spool does not correspond with the spool position command.

8. The method of claim 4 , wherein the testing for the fault condition of the second control valve includes monitoring a hydraulic flow through the second control valve and comparing the hydraulic flow with a reference flow command transmitted by a controller to the second control valve, and wherein the indicating of the valve fault occurs if the hydraulic flow through the second control valve does not correspond with the reference flow command.

9. The method of claim 2 , further comprising:
imposing an upper limit for output flow from the first control valve;
reducing an output pressure from the first control valve as the upper limit for the output flow from the first control valve is approached;
automatically reducing a pilot pressure that is pressurizing the second pilot of the second counter-balance valve, thereby closing the second counter-balance valve, and thereby stopping motion of the hydraulic actuator when the pilot pressure is sufficiently reduced.

10. The method of claim 4 , further comprising:
providing a valve between the first control valve and the second pilot of the second counter-balance valve;
regulating an output pressure from the valve if the valve fault is indicated and if a lower-override command is indicated;
regulating a pilot pressure that is pressurizing the second pilot of the second counter-balance valve by the regulating of the output pressure from the valve; and
throttling the second counter-balance valve by the regulating of the pilot pressure and thereby lowering an apparatus actuated by the hydraulic actuator.

11. The method of claim 4 , further comprising:
providing a valve between the first control valve and the second pilot of the second counter-balance valve; and
closing the valve when the valve fault is indicated.

12. The method of claim 1 , further comprising:
measuring a supply pressure;
determining whether a first chamber or a second chamber of the pair of chambers is a load holding chamber;
measuring a pressure of the load holding chamber;
determining if the supply pressure is greater than the pressure of the load holding chamber; and
reducing the supply pressure to less than the pressure of the load holding chamber if the supply pressure is greater than the pressure of the load holding chamber.

13. The method of claim 2 , further comprising:
monitoring a first hydraulic flow through the first control valve;
monitoring a second hydraulic flow through the second control valve;
testing for a fault condition of a hydraulic line between the second counter-balance valve and the second control valve;
indicating a hydraulic line fault if the fault condition is present;
regulating an output pressure from the first control valve if the hydraulic line fault is indicated and if a lower-override command is indicated;
regulating a pilot pressure that is pressurizing the second pilot of the second counter-balance valve by the regulating of the output pressure from the first control valve; and
throttling the second counter-balance valve by the regulating of the pilot pressure and thereby lowering an apparatus actuated by the hydraulic actuator;
operating the first control valve in a flow control mode if the hydraulic line fault is indicated and if a lower-override command is indicated;
providing a pilot pressure that is pressurizing the second pilot of the second counter-balance valve by regulating flow output from the first control valve; and
throttling the second counter-balance valve by the providing of the pilot pressure and thereby lowering an apparatus actuated by the hydraulic actuator.

14. A valve arrangement for use with a hydraulic actuator including a first chamber and a second chamber, the valve arrangement comprising:
a first counter-balance valve fluidly connected to the first chamber at a first node;
a second counter-balance valve fluidly connected to the second chamber at a second node;
a first control valve fluidly connected to the first counter-balance valve at a third node;
a second control valve fluidly connected to the second counter-balance valve at a fourth node; and
a normal operating mode wherein the second counter-balance valve is opened by the first control valve supplying a pressure to a second pilot of the second counter-balance valve, wherein the second control valve regulates an actuation velocity of the hydraulic actuator.

15. The valve arrangement of claim 14 , further comprising an override mode, wherein the second counter-balance valve is opened by the first control valve supplying a pressure to the second pilot of the second counter-balance valve, and wherein the second counter-balance valve regulates actuation of the hydraulic actuator.

16. The valve arrangement of claim 14 , further comprising:
a first valve fluidly connected to a first pilot of the first counter-balance valve at a fifth node a

Assignees

• Eaton Intelligent Power Ltd

Inventors

• Wang Meng
• Rannow Michael Berne

Classifications

• F15B11/042

  by means in the feed line {, i.e. "meter in"}(F15B11/046, F15B11/05 take precedence) · CPC title

• F15B21/008 Primary

  Reduction of noise or vibration · CPC title

• B66C13/066

  for minimising vibration of a boom · CPC title

• F15B2211/50509

  the pressure control means controlling a pressure upstream of the pressure control means · CPC title

• F15B19/005

  Fault detection or monitoring · CPC title