Abstract: An independent metering valve circuit includes an actuator, a set of independent metering valves, an independent metering valve pre-compensator, an inverse resolver, and a signal conditioning element. The set of independent metering valves are fluidly coupled to the actuator and configured to independently control a flow of a hydraulic fluid to the actuator. The independent metering valve pre-compensator is configured to control the flow of the hydraulic fluid to the set of independent metering valves. The inverse resolver is configured to receive a first pressure signal from the independent metering valve circuit and a second pressure signal from a load-sense hydraulic system and output a third pressure signal. The signal conditioning element is configured to receive the third pressure signal and output a forth pressure signal configured to control a pump fluidly coupled to the load-sense hydraulic system and the independent metering valve circuit.

Abstract: An independent metering valve circuit includes an actuator, a set of independent metering valves, an independent metering valve pre-compensator, an inverse resolver, and a signal conditioning element. The set of independent metering valves are fluidly coupled to the actuator and configured to independently control a flow of a hydraulic fluid to the actuator. The independent metering valve pre-compensator is configured to control the flow of the hydraulic fluid to the set of independent metering valves. The inverse resolver is configured to receive a first pressure signal from the independent metering valve circuit and a second pressure signal from a load-sense hydraulic system and output a third pressure signal. The signal conditioning element is configured to receive the third pressure signal and output a forth pressure signal configured to control a pump fluidly coupled to the load-sense hydraulic system and the independent metering valve circuit.

Abstract: This disclosure provides for pressure limiting a hydraulic system to a desired pressure value by a particular circuit by controlling and closing the compensator when the desired pressure setting is achieved. Closing the compensator will reduced the pressure head and flow in the circuit resulting in improved efficiency. One illustrated embodiment of the disclosure provides a relief valve in the pilot signal for a compensator. The method relates to limiting the pressure on an open side of the compensator, such that the pressure on the other side closes the compensator thereby limiting the pressure and also flow in the hydraulic circuit. In other words, the pressure on the open side is limited by the relief valve. Thus, the pressure on the other side increases thereby regulating the flow and pressure through the compensator.

Abstract: A hydraulic control system for a machine is disclosed. The hydraulic control system may have a hydraulic circuit, and a pump configured to supply pressurized fluid to the hydraulic circuit. The hydraulic control system may also have a first fluid actuator fluidly connected to receive pressurized fluid from the hydraulic circuit, a first valve arrangement movable to control a flow of fluid to the first fluid actuator, a second fluid actuator fluidly connected to receive pressurized fluid from the hydraulic circuit, and a second valve arrangement movable to control a flow of fluid to the second fluid actuator. The hydraulic control system may additionally have a controller in communication with the first and second valve arrangements. the controller may be configured to make a determination of a stall condition of the first fluid actuator, and to selectively change a flow command directed to the second valve arrangement based on the determination.

Abstract: A hydraulic system for a machine is disclosed. The hydraulic system may have a first pump with variable displacement and being load-sense controlled, and a first hydraulic circuit associated with the first pump. The hydraulic system may also have a second pump with variable displacement and being electro-hydraulically controlled, and a second hydraulic circuit associated with the second pump. The hydraulic system may further have a flow-sharing valve arrangement configured to selectively share fluid flow between the first and second hydraulic circuits.

Abstract: A hydraulic control system for a machine is disclosed. The hydraulic control system may have a hydraulic circuit, a pump configured to supply pressurized fluid, and a first sensor configured to generate a first signal indicative of a pressure of the hydraulic circuit. The hydraulic circuit may also have a first fluid actuator fluidly connected to receive pressurized fluid from the hydraulic circuit, a second sensor configured to generate a second signal indicative of a velocity of the first fluid actuator, and a controller in communication with the first and second sensors. The controller may be configured to receive an input indicative of a desired flow rate for the first fluid actuator, to determine an actual flow rate of the first fluid actuator based on the second signal, and to determine a stall condition of the first fluid actuator based on the desired flow rate, the actual flow rate, and the first signal.

Abstract: A computer-based method for calibrating a solenoid-controlled excess flow control valve that couples a first hydraulic circuit to a second hydraulic circuit is provided. The method includes determining a start-of-flow current at which hydraulic fluid begins to flow, closing the valve, sending an actuator command to the second hydraulic circuit, determining a first flow through the hydraulic actuator, opening the valve by setting the solenoid current to a calibration-flow current, sending the actuator command to the second hydraulic circuit, determining a second flow through the hydraulic actuator, calculating a flow difference, determining a calibration-flow valve command associated with the flow difference, determining a maximum-flow current based on the start-of-flow current, the calibration flow current, and the calibration-flow valve command, and creating a valve calibration table based on the start-of-flow current, the maximum-flow current and a valve response table.

Abstract: A control for a variable displacement pump disposed in a hydraulic system obtains a requested signal from a manual control device and provides a command signal to a valve operating to adjust a displacement setting of the variable displacement pump. The control provides the command signal based on the requested signal, and scales the requested signal based on a sensed or calculated load of the system.

Abstract: This disclosure provides for pressure limiting a hydraulic system to a desired pressure value by a particular circuit by controlling and closing the compensator when the desired pressure setting is achieved. Closing the compensator will reduced the pressure head and flow in the circuit resulting in improved efficiency. One illustrated embodiment of the disclosure provides a relief valve in the pilot signal for a compensator. The method relates to limiting the pressure on an open side of the compensator, such that the pressure on the other side closes the compensator thereby limiting the pressure and also flow in the hydraulic circuit. In other words, the pressure on the open side is limited by the relief valve. Thus, the pressure on the other side increases thereby regulating the flow and pressure through the compensator.

Abstract: A hydraulic control system for a machine is disclosed. The hydraulic control system may have a hydraulic circuit, and a pump configured to supply pressurized fluid to the hydraulic circuit. The hydraulic control system may also have a first fluid actuator fluidly connected to receive pressurized fluid from the hydraulic circuit, a first valve arrangement movable to control a flow of fluid to the first fluid actuator, a second fluid actuator fluidly connected to receive pressurized fluid from the hydraulic circuit, and a second valve arrangement movable to control a flow of fluid to the second fluid actuator. The hydraulic control system may additionally have a controller in communication with the first and second valve arrangements. the controller may be configured to make a determination of a stall condition of the first fluid actuator, and to selectively change a flow command directed to the second valve arrangement based on the determination.

Abstract: A hydraulic control system for a machine is disclosed. The hydraulic control system may have a hydraulic circuit, a pump configured to supply pressurized fluid, and a first sensor configured to generate a first signal indicative of a pressure of the hydraulic circuit. The hydraulic circuit may also have a first fluid actuator fluidly connected to receive pressurized fluid from the hydraulic circuit, a second sensor configured to generate a second signal indicative of a velocity of the first fluid actuator, and a controller in communication with the first and second sensors. The controller may be configured to receive an input indicative of a desired flow rate for the first fluid actuator, to determine an actual flow rate of the first fluid actuator based on the second signal, and to determine a stall condition of the first fluid actuator based on the desired flow rate, the actual flow rate, and the first signal.

Abstract: A hydraulic system for a machine is disclosed. The hydraulic system may have a first pump with variable displacement and being load-sense controlled, and a first hydraulic circuit associated with the first pump. The hydraulic system may also have a second pump with variable displacement and being electro-hydraulically controlled, and a second hydraulic circuit associated with the second pump. The hydraulic system may further have a flow-sharing valve arrangement configured to selectively share fluid flow between the first and second hydraulic circuits.

Abstract: A fluid system for use with a machine that employs an actuator, that provides for rapid shaking of an implement. The fluid system includes a source for providing fluid flow to the actuator and an operator input device for enabling an operator to control the movement of the implement by inputting a plurality of commands that specify movement of the implement. A controller is provided for monitoring the commands received from the operator input device and entering a mode for controlling the displacement of the source when the controller detects a pattern of commands that indicates an operator-request for rapid movement of the implement.

Abstract: A control for a variable displacement pump disposed in a hydraulic system obtains a requested signal from a manual control device and provides a command signal to a valve operating to adjust a displacement setting of the variable displacement pump. The control provides the command signal based on the requested signal, and scales the requested signal based on a sensed or calculated load of the system.

Abstract: A hydraulic circuit is disclosed. The hydraulic circuit may have a variable displacement pump. The variable displacement pump may have a fluidic displacement control configured to vary a flow of pressurized fluid based on a fluid signal and an electronic displacement control configured to vary the flow of pressurized fluid based on an electronic signal. The flow of pressurized fluid may be controlled by the one of the fluidic and electronic displacement controls that requests the smallest flow of pressurized fluid. The hydraulic circuit may also have a control valve connected between the pump and the fluidic displacement control, and the control valve may be configured to transmit the fluid signal to the fluidic displacement control.

Abstract: An energy recovery system for a machine is disclosed. The energy recovery system may have a pump configured to provide a flow of pressurized fluid. The energy recovery system may also have a first fluid actuator with a first chamber and a second chamber and being configured to receive the pressurized fluid, a second fluid actuator with a third chamber and a fourth chamber and being configured to receive the pressurized fluid, and a first valve fluidly connected between the pump and the first and second actuators. The energy recovery system may additionally include an isolation unit with a first selectively restrictable passageway fluidly connecting the first chamber, the third chamber, and a first outlet of the first valve, and a second selectively restrictable passageway fluidly connecting the second chamber, the fourth chamber, and a second outlet of the first valve, as well as an energy recovery unit in fluid communication with the isolation unit.

Abstract: A fluid system for use with a machine that employs an actuator, that provides for rapid shaking of an implement. The fluid system includes a source for providing fluid flow to the actuator and an operator input device for enabling an operator to control the movement of the implement by inputting a plurality of commands that specify movement of the implement. A controller is provided for monitoring the commands received from the operator input device and entering a mode for controlling the displacement of the source when the controller detects a pattern of commands that indicates an operator-request for rapid movement of the implement.

Abstract: A hydraulic circuit is disclosed. The hydraulic circuit may have a variable displacement pump. The variable displacement pump may have a fluidic displacement control configured to vary a flow of pressurized fluid based on a fluid signal and an electronic displacement control configured to vary the flow of pressurized fluid based on an electronic signal. The flow of pressurized fluid may be controlled by the one of the fluidic and electronic displacement controls that requests the smallest flow of pressurized fluid. The hydraulic circuit may also have a control valve connected between the pump and the fluidic displacement control, and the control valve may be configured to transmit the fluid signal to the fluidic displacement control.

Abstract: An energy recovery system for a machine is disclosed. The energy recovery system may have a pump configured to provide a flow of pressurized fluid. The energy recovery system may also have a first fluid actuator with a first chamber and a second chamber and being configured to receive the pressurized fluid, a second fluid actuator with a third chamber and a fourth chamber and being configured to receive the pressurized fluid, and a first valve fluidly connected between the pump and the first and second actuators. The energy recovery system may additionally include an isolation unit with a first selectively restrictable passageway fluidly connecting the first chamber, the third chamber, and a first outlet of the first valve, and a second selectively restrictable passageway fluidly connecting the second chamber, the fourth chamber, and a second outlet of the first valve, as well as an energy recovery unit in fluid communication with the isolation unit.

Abstract: A cylinder assembly is disclosed. The cylinder assembly may include a cylinder body having an internal cavity therein and a piston and rod assembly disposed for axial movement within the internal cavity of the cylinder body. The piston and rod assembly may have an axial passage extending therein. The cylinder assembly may further include a tubular element received within the axial passage of the piston and rod assembly. At least a portion of the tubular element may extend out of the axial passage and into the internal cavity of the cylinder body between the axial passage and a wall of the cylinder body.