Electro-hydraulic valve control system and method
First Claim
1. A method of controlling an electro-hydraulic valve arrangement disposed in fluid connection between a source of pressurized fluid and an actuator, comprising:
- receiving a signal to open the electro-hydraulic valve arrangement to provide a flow of fluid from the source of pressurized fluid to the actuator;
determining a source pressure representative of the pressure of fluid between the source of pressurized fluid and the electro-hydraulic valve arrangement;
determining an actuator pressure representative of the pressure of the fluid between the electro-hydraulic valve arrangement and the actuator modifying the received signal to prevent the electro-hydraulic valve arrangement from opening when the source pressure is less than the actuator pressure to prevent a reverse flow of fluid from the actuator to the source of pressurized fluid; and
modifying the received signal to close the electro-hydraulic valve arrangement when the source pressure drops below the actuator pressure.
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Accused Products
Abstract
A system and method for controlling an electro-hydraulic valve arrangement to perform a pump check function are provided. The system includes an electro-hydraulic valve arrangement disposed between a source of pressurized fluid and a hydraulic actuator. Pressure sensors are provided to sense a source pressure representative of the fluid pressure between the source of pressurized fluid and the electro-hydraulic valve arrangement and an actuator pressure representative of the fluid pressure between the electro-hydraulic valve arrangement and the actuator. A control device receives a signal to open the electro-hydraulic valve arrangement to provide a requested flow rate to the hydraulic actuator. The received signal is modified to prevent fluid flow through the electro-hydraulic valve arrangement when the source pressure is less than the actuator pressure.
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Citations
18 Claims
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1. A method of controlling an electro-hydraulic valve arrangement disposed in fluid connection between a source of pressurized fluid and an actuator, comprising:
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receiving a signal to open the electro-hydraulic valve arrangement to provide a flow of fluid from the source of pressurized fluid to the actuator;
determining a source pressure representative of the pressure of fluid between the source of pressurized fluid and the electro-hydraulic valve arrangement;
determining an actuator pressure representative of the pressure of the fluid between the electro-hydraulic valve arrangement and the actuator modifying the received signal to prevent the electro-hydraulic valve arrangement from opening when the source pressure is less than the actuator pressure to prevent a reverse flow of fluid from the actuator to the source of pressurized fluid; and
modifying the received signal to close the electro-hydraulic valve arrangement when the source pressure drops below the actuator pressure. - View Dependent Claims (2)
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3. A method of controlling an electro-hydraulic valve arrangement disposed in fluid connection between a source of pressurized fluid and an actuator, comprising:
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receiving a signal to open the electro-hydraulic valve arrangement to provide a flow of fluid from the source of pressurized fluid to the actuator;
determining a source pressure representative of the pressure of fluid between the source of pressurized fluid and the electro-hydraulic valve arrangement;
determining an actuator pressure representative of the pressure of the fluid between the electro-hydraulic valve arrangement and the actuator;
modifying the received signal to prevent the electro-hydraulic valve arrangement from opening when the source pressure is less than the sum of the actuator pressure and a safety margin to prevent a reverse flow of fluid from the actuator to the source of pressurized fluid.
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4. A method of controlling an electro-hydraulic valve arrangement disposed in fluid connection between a source of pressurized fluid and an actuator, comprising the steps of:
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determining a requested flow rate of fluid to be provided to the actuator based on load conditions;
determining a source pressure representative of the pressure of fluid between the source of pressurized fluid and the electro-hydraulic valve arrangement;
determining an actuator pressure representative of the pressure of the fluid between the electro-hydraulic valve arrangement and the actuator;
computing a scaling factor based on the difference between the source pressure and the actuator pressure;
applying the scaling factor to the requested flow rate to determine an actual flow rate of fluid to provide to the actuator; and
adjusting the electro-hydraulic valve arrangement to a position where the actual flow rate of fluid is provided to the actuator. - View Dependent Claims (5, 6, 7, 8, 9, 10)
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11. A system for controlling a hydraulic actuator, comprising:
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a hydraulic actuator;
a source of pressurized fluid;
an electro-hydraulic valve arrangement in fluid connection with the source of pressurized fluid and the hydraulic actuator and operable to control a flow rate of fluid from the source of pressurized fluid to the hydraulic actuator;
a first pressure sensor operable to sense a source pressure representative of the pressure of the fluid between the source of pressurized fluid and the electro-hydraulic valve arrangement;
a second pressure sensor operable to sense an actuator pressure representative of the pressure of the fluid between the electro-hydraulic valve arrangement and the hydraulic actuator; and
a control device for controlling the electro-hydraulic valve arrangement, the control device operable to receive a signal to open the electro-hydraulic valve arrangement and prevent the electro-hydraulic valve arrangement from opening when the source pressure is less than the actuator pressure, wherein the control device is further operable to close the electro-hydraulic valve arrangement when the source pressure drops below the actuator pressure.
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12. A system for controlling a hydraulic actuator, comprising:
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a hydraulic actuator including a first chamber and a second chamber;
a source of pressurized fluid;
an electro-hydraulic valve arrangement in fluid connection with the source of pressurized fluid and the hydraulic actuator and including a series of independent metering valves adapted to control a flow of fluid into and out of the first and second chambers of the hydraulic actuator;
a first pressure sensor operable to sense a source pressure representative of the pressure of the fluid between the source of pressurized fluid and the electro-hydraulic valve arrangement;
a second pressure sensor operable to sense an actuator pressure representative of the pressure of the fluid between the electro-hydraulic valve arrangement and the hydraulic actuator; and
a control device for controlling the electro-hydraulic valve arrangement, the control device operable to receive a signal to open the electro-hydraulic valve arrangement and prevent the electro-hydraulic valve arrangement from opening when the source pressure is less than the actuator pressure. - View Dependent Claims (13, 14)
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15. A system for controlling a hydraulic actuator, comprising:
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a hydraulic actuator;
a source of pressurized fluid;
an electro-hydraulic valve arrangement in fluid connection with the source of pressurized fluid and the hydraulic actuator and operable to control a flow rate of fluid from the source of pressurized fluid to the hydraulic actuator;
a first pressure sensor operable to sense a source pressure representative of the pressure of the fluid between the source of pressurized fluid and the electro-hydraulic valve arrangement;
a second pressure sensor operable to sense an actuator pressure representative of the pressure of the fluid between the electro-hydraulic valve arrangement and the hydraulic actuator;
a control device for controlling the electro-hydraulic valve arrangement, the control device operable to receive a signal to open the electro-hydraulic valve arrangement and prevent the electro-hydraulic valve arrangement from opening when the source pressure is less than the actuator pressure; and
a remote control operable to generate the signal to open the electro-hydraulic valve arrangement.
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16. A system for controlling a hydraulic actuator, comprising:
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a hydraulic actuator;
a source of pressurized fluid;
an electro-hydraulic valve arrangement in fluid connection with the source of pressurized fluid and the hydraulic actuator and operable to control a flow rate of fluid from the source of pressurized fluid to the hydraulic actuator;
a first pressure sensor operable to sense a source pressure representative of the pressure of the fluid between the source of pressurized fluid and the electro-hydraulic valve arrangement;
a second pressure sensor operable to sense an actuator pressure representative of the pressure of the fluid between the electro-hydraulic valve arrangement and the hydraulic actuator; and
a control device for controlling the electro-hydraulic valve arrangement, the control device operable to receive a signal to open the electro-hydraulic valve arrangement to provide a requested fluid flow, the control device further operable to compute a scaling factor based on the difference between the source pressure and the actuator pressure and to open the electro-hydraulic valve arrangement to provide an actual fluid flow based on the application of the scaling factor to the requested fluid flow. - View Dependent Claims (17, 18)
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Specification