Hydraulic control system with cross function regeneration

In a hydraulic system that includes a plurality of hydraulic functions connected to a supply conduit carrying pressurized fluid from a source and to a return conduit connected to a tank, at least one hydraulic function comprising a cylinder with a piston that defines a rod chamber and a head chamber in the cylinder, a first valve coupling the head chamber to the supply conduit, a second valve coupling the rod chamber to the supply conduit, a third valve coupling the head chamber to the return conduit, and a fourth valve coupling the rod chamber to the return conduit, a method for operating the at least one hydraulic function comprising:

• receiving a command designating desired motion of the piston;
• determining a hydraulic load acting on the cylinder;
• indicating a first pressure present in the supply conduit;
• indicating a second pressure present in the return conduit;
• in response to the command, the hydraulic load, the first pressure and the second pressure, selecting a metering mode from among a Standard Powered Retraction (Piston Extend) mode, a Standard Powered Extension (Piston Extend) mode, a Standard Powered Extension (Piston Retract) mode, and a Standard Powered Retraction (Piston Retract) mode;
• and
• in response to the metering mode selected, opening two of the first, second, third and fourth valves as defined in the following table:
• Metering Mode
• Valves Opened
• Standard Powered Retraction (Piston Extend)
• second and third valves
• Low Side Regeneration Extension
• third and fourth valves
• High Side Regeneration Extension
• first and second valves
• Standard Powered Extension (Piston Extend)
• first and fourth valves.
• Standard Powered Extension (Piston Retract)
• first and fourth valves
• High Side Regeneration Retraction
• first and second valves
• Low Side Regeneration Retraction
• third and fourth valves
• Standard Powered Retraction (Piston Retract)
• second and third valves.

In a hydraulic system that includes a plurality of hydraulic functions connected to a supply conduit carrying pressurized fluid from a source and to a return conduit connected to a tank, at least one hydraulic function comprising hydraulic actuator with a first port and a second port, a first valve coupling the first port to the supply conduit, a second valve coupling the second port to the supply conduit, a third valve coupling the first port to the return conduit, and a fourth valve coupling the second port to the return conduit, a method for operating the at least one hydraulic function comprising:

• receiving a command designating desired motion of the hydraulic actuator;
• sensing a parameter that indicates a magnitude of a hydraulic load acting on the hydraulic actuator;
• sensing pressure in the hydraulic system;
• and
• in response to the command, the hydraulic load and the pressure, selecting a metering mode among a first metering mode in which the first and fourth valves are opened wherein fluid from the supply conduit drives the hydraulic actuator in a first direction, a second metering mode in which the second and third valves are opened wherein fluid from the supply conduit drives the hydraulic actuator in a second direction, and a third metering mode in which the first and fourth valves are opened while the hydraulic actuator is moving in the second direction wherein fluid flow from the hydraulic actuator into the supply conduit and from the return conduit to the hydraulic actuator.

In a hydraulic system that includes a plurality of hydraulic functions connected to a supply conduit carrying pressurized fluid from a source and to a return conduit connected to a tank, each hydraulic function comprising a piston-cylinder arrangement with a first chamber and a second chamber both coupled by a valve assembly to the supply conduit and to the return conduit, a method for operating one hydraulic function comprising:

• receiving a command designating desired motion of the hydraulic actuator;
• sensing a hydraulic load acting on the hydraulic actuator;
• sensing a pressure value denoting a pressure present in the hydraulic system;
• and
• in response to the command, the hydraulic load and the pressure value, operating the valve assembly to direct fluid from the first chamber into both the second chamber and the supply conduit.