Abstract: Systems and methods for estimating the area ratio of an actuator in static and dynamic states are disclosed. In one aspect, a metering valve is connected to each side of the actuator. In one example, one metering valve is held closed while the other metering valve incrementally pressurizes the actuator in discrete steps. The resulting work port pressures can be used to determine the actuator area ratio. Where counterbalance valves are installed in the system, the pressurizing metering valve can be placed in a pressure control mode to obtain the desired pressure values. In one example, the ratio of flows through each metering valve is used to determine the actuator ratio.

Abstract: An energy conserving hydraulic system for a mobile work machine includes a prime mover, a drivetrain, a baseline hydraulic system, a power-take-off, a transformer, a work implement, and an accumulator. The drivetrain may include an automated manual transmission (AMT) that is rotationally coupled to the prime mover and the power-take-off. The baseline hydraulic system is powered by the prime mover and includes a first hydraulic circuit. The transformer is hydraulically coupled to second and third hydraulic circuits. The work implement is actuated by an actuator that is adapted to be simultaneously hydraulically coupled to the first and the second hydraulic circuits. The power-take-off is adapted to exchange shaft power with the transmission. A clutch selectively rotationally couples the transmission and the power-take-off. The accumulator is hydraulically coupled to the second hydraulic circuit.

Abstract: Systems and methods for controlling valve assemblies associated with an actuator in an electro-hydraulic system are disclosed. In one method, a controller monitors hydraulic fluid flow for an actuator to identify one valve assembly connected to the actuator as a meter-in valve and another valve assembly connected to the actuator as a meter-out valve. In one aspect, the valve assembly most recently identified as the meter-in valve is controlled to maintain a pressure setpoint and the valve assembly most recently identified as the meter-out valve is controlled to maintain a hydraulic fluid flow rate. The method can also include determining whether the actuator is in a passive state or an overrunning state and controlling the valve most recently identified as the meter-in valve to maintain a first pressure setpoint when the actuator is in a passive state and to maintain a second pressure setpoint when the actuator is in an overrunning state.

Abstract: A hydraulic system (600) and method for reducing boom dynamics of a boom (30), while providing counter-balance valve protection, includes a hydraulic actuator (110), first and second counter-balance valves (300, 400), first and second control valves (700, 800), and first and second blocking valves (350, 450). A net load (90) is supported by a first chamber (116, 118) of the hydraulic actuator, and a second chamber (118, 116) of the hydraulic actuator may receive fluctuating hydraulic fluid flow from the second control valve to produce a vibratory response (950) that counters environmental vibrations (960) on the boom. The first blocking valve prevents the fluctuating hydraulic fluid flow from opening the first counter-balance valve. The first blocking valve may drain leakage from the first counter-balance valve.

Abstract: A hydraulic system (600) and method for reducing boom dynamics of a boom (30), while providing counter-balance valve protection, includes a hydraulic actuator (110), first and second counter-balance valves (300, 400), first and second independent control valves (700, 800), and first and second blocking valves (350, 450). The actuator includes first and second corresponding chambers. In a first mode, the second counter-balance valve is opened by the first control valve, and the first counter-balance valve is opened by the second control valve. In a second mode, at least one of the counter-balance valves is closed. A meter-out control valve (800, 700) may be operated in a flow control mode, and/or a meter-in control valve (700, 800) may be operated in a pressure control mode. Boom dynamics reduction may occur while the boom is in motion (e.g., about a worksite). By opening the counter-balance valves, sensors at the control valves may be used to characterize external loads.

Abstract: A hydraulic system (600) and method for reducing boom dynamics of a boom (30), while providing counter-balance valve protection, includes a hydraulic cylinder (110), first and second counter-balance valves (300, 400), first and second control valves (700, 800), and first and second blocking valves (350, 450). A net load (90) is supported by a first chamber (116, 118) of the hydraulic cylinder, and a second chamber (118, 116) of the hydraulic cylinder may receive fluctuating hydraulic fluid flow from the second control valve to produce a vibratory response (950) that counters environmental vibrations (960) on the boom. The method may include measuring first pressure ripples at the second chamber and reducing a magnitude of second pressure ripples at the first chamber. The pressure ripples may be transformed into a flow command by multiplying the pressure ripples by a gain and/or phase shifting. The gain and/or the phase shifting may be adjusted by feedback.

Abstract: A hydraulic system (600) and method for reducing boom dynamics of a boom (30), while providing counter-balance valve protection, includes a hydraulic cylinder (110), first and second counter-balance valves (300, 400), and first and second control valves (700, 800). A net load (90) is supported by a first chamber (116, 118) of the hydraulic cylinder, and a second chamber (118, 116) of the hydraulic cylinder may receive fluctuating hydraulic fluid flow from the second control valve to produce a vibratory response (950) that counters environmental vibrations (960) on the boom. The first control valve may apply a holding pressure and thereby hold the first counter-balance valve closed and the second counter-balance valve open.

Abstract: The present disclosure relates to a load dependent flow control system for directing hydraulic fluid to a hydraulic actuator. The load dependent flow control system includes a closed-center valve device for controlling hydraulic fluid flow to the actuator. The closed-center valve device includes a valve spool and an electro-actuator that adjusts a position of the valve spool to adjust a rate of the hydraulic fluid flow supplied to the hydraulic actuator. A pressure sensor is provided for sensing a pressure of the hydraulic fluid provided to the hydraulic actuator. The system also includes an electronic controller configured to receive an operator flow command from an operator interface. The operator flow command corresponds to a base flow through the closed-center valve device. The electronic controller interfaces with the electro-actuator of the closed-center valve device and with the pressure sensor.

Abstract: An online method for reconfiguring pressure and position sensors in a hydraulic system is disclosed. In one step, a sensor drift condition, a recalibration request, or an unisolated fault condition is detected. In another step, a system pressure sensor or another sensor, such as a load-sense pressure sensor, is verified as a trusted master reference sensor. Another step includes measuring and recording a first pressure reading at the master reference sensor and first voltage readings associated with first, second, third, and fourth pressure slave sensors at a first pump pressure set point. Another step includes, repeating the previous step at a second pump pressure set point. A new gain and offset for each of the first, second, third, and fourth pressure sensors can be calculated based on a comparison of the recoded first and second pressure readings and the recorded first and second voltage readings.

Abstract: A hydraulic system (600) and method for reducing boom dynamics of a boom (30), while providing counter-balance valve protection, includes a hydraulic cylinder (110), first and second counter-balance valves (300, 400), and first and second control valves (700, 800). A net load (90) is supported by a first chamber (116, 118) of the hydraulic cylinder, and a second chamber (118, 116) of the hydraulic cylinder may receive fluctuating hydraulic fluid flow from the second control valve to produce a vibratory response (950) that counters environmental vibrations (960) on the boom. The first control valve may apply a holding pressure and thereby hold the first counter-balance valve closed and the second counter-balance valve open.

Abstract: The present disclosure relates to fault detection, isolation and reconfiguration schemes, architectures and methods for use in electrohydraulic actuation systems for construction equipment. In one embodiment, a supervisory controller adapted to interface with a main controller of the construction vehicle is provided. A plurality of control nodes that interface with the supervisory controller are also disclosed, each of which includes pressure and position sensors. The nodes also include a first actuator control node for controlling operation of a first hydraulic actuator, a second actuator control node for controlling operation of a second hydraulic actuator, and a pump control node. The control system has an architecture in which faults are detected and isolated at the supervisory controller level and, where possible, within each of the control nodes at a sensor level, a component level, and a subsystem level.

Abstract: Systems and methods for controlling valve assemblies associated with an actuator in an electro-hydraulic system are disclosed. In one method, a controller monitors hydraulic fluid flow for an actuator to identify one valve assembly connected to the actuator as a meter-in valve and another valve assembly connected to the actuator as a meter-out valve. In one aspect, the valve assembly most recently identified as the meter-in valve is controlled to maintain a pressure setpoint and the valve assembly most recently identified as the meter-out valve is controlled to maintain a hydraulic fluid flow rate. The method can also include determining whether the actuator is in a passive state or an overrunning state and controlling the valve most recently identified as the meter-in valve to maintain a first pressure setpoint when the actuator is in a passive state and to maintain a second pressure setpoint when the actuator is in an overrunning state.

Abstract: Systems and methods for estimating the area ratio of an actuator in static and dynamic states are disclosed. In one aspect, a metering valve is connected to each side of the actuator. In one example, one metering valve is held closed while the other metering valve incrementally pressurizes the actuator in discrete steps. The resulting work port pressures can be used to determine the actuator area ratio. Where counterbalance valves are installed in the system, the pressurizing metering valve can be placed in a pressure control mode to obtain the desired pressure values. In one example, the ratio of flows through each metering valve is used to determine the actuator ratio.

Abstract: Systems and methods for auto-commissioning first and second valve assemblies associated with an actuator in an electro-hydraulic system are disclosed. In one method, a controller performs an automatic test protocol to determine a bulk modulus over fluid volume parameter used by the controller to control the valve assemblies. In one aspect, the test protocol can include pressurizing each side of the actuator to two different pressures with one of the first and second valve assemblies and blocking the other side of the actuator with the other of the first and second valve assemblies. The bulk modulus over fluid volume parameter for each valve assembly can be calculated based on recorded fluid pressures at the actuator and consumed flow at the first and second valve assemblies.

Abstract: A system and method for detecting a leak in a hose of a hydraulic system having a control valve assembly with first and second work ports in fluid communication with an actuator is disclosed. In one aspect, the method includes estimating a first hydraulic fluid flow rate for fluid flowing from the control valve assembly first work port to the actuator. Another step may be estimating a second hydraulic fluid flow rate for fluid flowing from the actuator to the control valve assembly second work port. In one step, a proportional flow rate difference is calculated between the first and second hydraulic fluid flow rates. Subsequently, a flow error value can be calculated by subtracting the flow rate difference from a predetermined margin value. Where the flow error value integrated over time exceeds a total flow error threshold value, a hydraulic fluid leak signal can be generated.

Abstract: A hydraulic system (600) and method for reducing boom dynamics of a boom (30), while providing counter-balance valve protection, includes a hydraulic actuator (110), first and second counter-balance valves (300, 400), first and second independent control valves (700, 800), and first and second blocking valves (350, 450). The actuator includes first and second corresponding chambers. In a first mode, the second counter-balance valve is opened by the first control valve, and the first counter-balance valve is opened by the second control valve. In a second mode, at least one of the counter-balance valves is closed. A meter-out control valve (800, 700) may be operated in a flow control mode, and/or a meter-in control valve (700, 800) may be operated in a pressure control mode. Boom dynamics reduction may occur while the boom is in motion (e.g., about a worksite). By opening the counter-balance valves, sensors at the control valves may be used to characterize external loads.

Abstract: A method for isolating a fault or blocked work port in an electro-hydraulic system is disclosed. In one step, a system pump is set to a first predetermined pressure and a valve assembly is commanded to a center position. In another step, the center position of the valve is recorded. In one step, the valve assembly is opened to place a work port associated with the valve in fluid communication with the pump, after which a first end position of the valve, a first work port pressure, and a first pump supply pressure are recorded. In another step, the valve assembly is opened to place the work port to a tank reservoir, after which a second end position of the valve and a fluid pressure associated with the work port are recorded. The recorded and measured data can then be analyzed to identify the fault condition or blocked work port.

Abstract: An energy conserving hydraulic system for a mobile work machine includes a prime mover, a drivetrain, a baseline hydraulic system, a power-take-off, a transformer, a work implement, and an accumulator. The drivetrain may include an automated manual transmission (AMT) that is rotationally coupled to the prime mover and the power-take-off. The baseline hydraulic system is powered by the prime mover and includes a first hydraulic circuit. The transformer is hydraulically coupled to second and third hydraulic circuits. The work implement is actuated by an actuator that is adapted to be simultaneously hydraulically coupled to the first and the second hydraulic circuits. The power-take-off is adapted to exchange shaft power with the transmission. A clutch selectively rotationally couples the transmission and the power-take-off. The accumulator is hydraulically coupled to the second hydraulic circuit.

Abstract: An online method for reconfiguring pressure and position sensors in a hydraulic system is disclosed. In one step, a sensor drift condition, a recalibration request, or an unisolated fault condition is detected. In another step, a system pressure sensor or another sensor, such as a load-sense pressure sensor, is verified as a trusted master reference sensor. Another step includes measuring and recording a first pressure reading at the master reference sensor and first voltage readings associated with first, second, third, and fourth pressure slave sensors at a first pump pressure set point. Another step includes, repeating the previous step at a second pump pressure set point. A new gain and offset for each of the first, second, third, and fourth pressure sensors can be calculated based on a comparison of the recoded first and second pressure readings and the recorded first and second voltage readings.

Abstract: A hydraulic system (600) and method for reducing boom dynamics of a boom (30), while providing counter-balance valve protection, includes a hydraulic actuator (110), first and second counter-balance valves (300, 400), first and second control valves (700, 800), and first and second blocking valves (350, 450). A net load (90) is supported by a first chamber (116, 118) of the hydraulic actuator, and a second chamber (118, 116) of the hydraulic actuator may receive fluctuating hydraulic fluid flow from the second control valve to produce a vibratory response (950) that counters environmental vibrations (960) on the boom. The first blocking valve prevents the fluctuating hydraulic fluid flow from opening the first counter-balance valve. The first blocking valve may drain leakage from the first counter-balance valve.