System and method for controlling an independent metering valve
AssigneeCaterpillar Inc.
InventorsJames A. Aardema, Douglas W. Koehler
Life of this patent
Estimating the term…
Abstract
A system and method for controlling an independent metering valve operating in a hydraulic circuit determines a displacement command for one or more metering valves to provide desired flows through the metering valves and desired pressure drops across the metering valves. The system determines the displacement command based on a mode of operation of the hydraulic circuit and a velocity for a hydraulic device controlled by the hydraulic circuit. The system determines the displacement command further based on an amount of flow available to the hydraulic circuit. The system allows the hydraulic circuit to be electronically controlled thereby providing flexibility not found in conventional hydraulic control systems.
Claims31
A system for controlling a hydraulic circuit including a metering valve and a hydraulic device, the system comprising:
- flow determining means for determining a desired flow through the metering valve based on a requested velocity;
- pressure drop determining means for determining a desired pressure drop across the metering valve;
- offset determining means for determining an offset associated with the metering valve;
- displacement determining means for determining a displacement for the metering valve from said desired flow and said desired pressure drop and said offset;
- and
- actuating means for actuating the metering valve based on said displacement to control the hydraulic device in the hydraulic circuit.
A system for controlling a hydraulic circuit including a hydraulic device and a plurality of metering valves, the system comprising:
- flow determining means for determining a desired flow through each of the plurality of metering valves based on a requested velocity and an amount of flow available to the hydraulic circuit;
- pressure drop determining means for determining a desired pressure drop across each of the plurality of metering valves;
- displacement determining means for determining a displacement for each of the plurality of metering valves based on said desired flow and said pressure drop associated with each of the plurality of metering valves;
- and
- actuating means for actuating each of the plurality of metering valves based on said displacement associated with each of the plurality of metering valves to control the hydraulic device in the hydraulic circuit.
A system for controlling a plurality of hydraulic circuits, each of the plurality of hydraulic circuit having a plurality of metering valves, the system comprising:
- flow determining means for determining a desired flow through each of the plurality of metering valves in each of the plurality of hydraulic circuits based on a requested velocity and an amount of flow available to each of the plurality of hydraulic circuits;
- pressure drop determining means for determining a desired pressure drop across each of the plurality of metering valves in each of the plurality of hydraulic circuits;
- and
- displacement determining means for determining a displacement for each of the plurality of metering valves in each of the plurality of hydraulic circuits based on said desired flow and said desired pressure drop associated with each of the plurality of metering valves in each of the plurality of hydraulic circuits.
A system for controlling a hydraulic circuit including an independent metering valve and a hydraulic cylinder, the independent metering valve including an input port, an output port, first and second control ports, first and second independently operable electrohydraulic metering valves disposed between the input port and the first and second control ports, and third and fourth independently operable electrohydraulic metering valves disposed between the output port and the first and second control ports, the system comprising:
- a flow determinator that determines a desired flow through at least one of the first, second, third, and fourth metering valves based on a requested velocity;
- a pressure drop determinator that determines a desired pressure drop across said at least one of the first, second, third, and fourth metering valves based on a pump pressure, a head pressure of the hydraulic cylinder, and a rod pressure of the hydraulic cylinder;
- and
- a displacement determinator that determines a displacement for said at least one of the first, second, third, and fourth metering valves based on said desired flow and said desired pressure drop.
Dependencies are inferred from the claim text.