System and method for calibrating electrohydraulic valve

1. A method of calibrating an electrohydraulic valve, the method comprising:

actuating an on-off valve to an open position,

wherein the on-off valve is initially in a closed position, and

wherein the on-off valve is configured to provide a set flow restriction to a fluid flow therethrough in the open position, with flow through the on-off valve having a known pressure at a known flow rate;

regulating a speed of a fixed displacement pump to establish a desired flow rate at an outlet of the fixed displacement pump,

wherein the fixed displacement pump is in fluid communication within a closed loop circuit with the on-off valve and the electrohydraulic valve;

determining a target pressure in the closed loop circuit as a function of the desired flow rate;

increasing a current to the electrohydraulic valve;

monitoring the target pressure in the closed loop circuit; and

determining a start of a fluid flow through the electrohydraulic valve based on a drop in the target pressure within the closed loop circuit.

2. The method of claim 1 , wherein the on-off valve is a two-port two-way valve.

3. The method of claim 1 , wherein regulating the speed of the fixed displacement pump comprises varying a speed of a motor operatively coupled with the fixed displacement pump.

4. The method of claim 1 , further comprising determining a cracking current of the electrohydraulic valve based on a value of the current provided to the electrohydraulic valve coinciding with the drop in the target pressure within the closed loop circuit.

5. The method of claim 1 , further comprising actuating an additional electrohydraulic valve to an open position, wherein the additional electrohydraulic valve is in fluid communication with a tank.

6. A method of calibrating a first electrohydraulic valve configured to control fluid flow from a pump to a cylinder and a second electrohydraulic valve configured to control fluid flow from the cylinder to a tank, the method comprising:

opening an on-off valve in a closed loop circuit that includes the first electrohydraulic valve and the pump,

wherein the on-off valve is initially in a closed position, and

wherein the on-off valve is configured to provide set flow restrictions to fluid flow therethrough in the open position, with flow through the on-off valve having a known pressure at a known flow rate;

actuating the second electrohydraulic valve to an open position;

regulating a speed of the pump to establish a desired flow rate at an outlet of the pump,

wherein the desired flow rate from the pump results in a target pressure in the closed loop circuit;

increasing a current to the first electrohydraulic valve;

monitoring the target pressure in the closed loop circuit;

determining a start of a fluid flow through the first electrohydraulic valve based on a first drop in the target pressure in the closed loop circuit;

actuating the first electrohydraulic valve and the second electrohydraulic valve to closed positions while maintaining the on-off valve in an open position;

actuating the first electrohydraulic valve to an open position;

increasing a current to the second electrohydraulic valve;

monitoring pressure of the fluid flow in the closed loop circuit; and

determining a start of a fluid flow through the second electrohydraulic valve based on a second drop in the pressure of the fluid flow in the closed loop circuit.

7. The method of claim 6 , wherein the on-off valve is a two-port two-way valve.

8. The method of claim 6 , wherein regulating the speed of the pump comprises varying a speed of a motor operatively coupled with the pump.

9. The method of claim 6 , further comprising determining a cracking current of the first electrohydraulic valve based on a value of the current provided to the first electrohydraulic valve coinciding with the first drop in the target pressure in the closed loop circuit.

10. The method of claim 6 , further comprising determining a cracking current of the second electrohydraulic valve based on a value of the current provided to the second electrohydraulic valve coinciding with the second drop in the pressure of the fluid flow in the closed loop circuit.

11. A system for calibrating an electrohydraulic valve, the system comprising:

a pump configured to pressurize a fluid,

wherein the pump is in fluid communication with the electrohydraulic valve;

an on-off valve disposed in fluid communication with the pump,

wherein the on-off valve is initially in a closed position, and

wherein the on-off valve is configured to provide a flow restriction to a fluid flow therethrough in the open position, with flow through the on-off valve having a known pressure at a known flow rate; and

a controller communicably coupled to the electrohydraulic valve, the pump, and the on-off valve,

the controller configured to:

actuate the on-off valve to an open position;

regulate speed of the pump to establish a desired flow rate at the outlet of the pump,

the desired flow rate from the pump resulting in a target pressure as a result of passage through the on-off valve;

increase a current to the electrohydraulic valve;

monitor the target pressure; and

determine a start of a fluid flow through the electrohydraulic valve based on a drop in the target pressure.

12. The system of claim 11 , wherein the electrohydraulic valve is electrically actuated by the controller.

13. The system of claim 11 , wherein the on-off valve is a solenoid valve.

14. The system of claim 11 , wherein the pump comprises a variable speed motor configured to be regulated by the controller.

15. The system of claim 11 , wherein the controller is further configured to determine a cracking current of the electrohydraulic valve based on a value of the current provided to the electrohydraulic valve coinciding with the drop in the target pressure.

16. The system of claim 11 , further comprising an additional electrohydraulic valve in fluid communication with a tank.

17. The system of claim 16 , wherein the controller is further configured to actuate the additional electrohydraulic valve to an open position.

18. The system of claim 16 , wherein the controller is further configured to:

actuate the electrohydraulic valve and the additional electrohydraulic valve to closed positions;

actuate the electrohydraulic valve to an open position;

increasing a current to the additional electrohydraulic valve; and

determine a start of a fluid flow through the additional electrohydraulic valve based on a drop in the pressure of the fluid flow.

19. The system of claim 16 , further comprising an actuator,

wherein the actuator comprises a chamber in fluid communication with the electrohydraulic valve and the additional electrohydraulic valve.

20. The system of claim 19 , wherein the actuator is a hydraulic cylinder.