Abstract: A hydraulic control system is disclosed for use with a machine. The hydraulic control system may have a tank, a pump, a swing motor, and at least one control. The hydraulic control system may further have an accumulator configured to receive fluid from and supply fluid to the swing motor, a charge valve movable to allow fluid flow from the swing motor into the accumulator, and a discharge valve movable to allow fluid flow from the accumulator to the swing motor. The hydraulic control system may additionally have a controller in communication with the at least one control valve, the charge valve, and the discharge valve. The controller may be configured to detect an acceleration of the swing motor, selectively cause the discharge valve to assist the acceleration, and selectively move the charge valve to an open position to recover energy associated with pressure spikes occurring during the acceleration.

Abstract: A system to diagnose a health of a hydraulic accumulator is provided. The hydraulic accumulator includes a first fluid chamber, a second fluid chamber, and a separator. The hydraulic accumulator has an associated pre-charge pressure. The system further includes a pressure sensor, a fluid source, a data processor, and a comparator. The pressure sensor and the fluid source are connected to the first fluid chamber. The data processor is configured to determine a first and second rate of pressure changes, and a transition pressure between the first and second rates. The approximate pre-charge pressure is determined based on the transition pressure. The comparator is configured to compare at least one of the determined pre charge pressure and the frictional forces with a pre-determined threshold range of pre-charge pressure and the frictional forces associated with the hydraulic accumulator to diagnose the health of the hydraulic accumulator.

Abstract: A hydraulic control system is disclosed. The hydraulic control system may have an input device to generate a first signal indicative of a desired swing motor movement, and a control valve configured to selectively pass fluid to the swing motor and drain from the swing motor to drive the swing motor based on the first signal. The hydraulic control system may also have a pressure sensor to generate a second signal indicative of a swing motor pressure, a speed sensor configured to a third signal indicative of a swing motor speed, and a controller configured to make a comparison of at least one of the swing motor speed and the swing motor pressure with a threshold speed and a threshold pressure, and open the control valve to drain fluid from the swing motor to the tank based on the comparison when the input device is in a neutral condition.

Abstract: A hydraulic control system is disclosed for use with a machine. The hydraulic control system may have a tank, a pump, an actuator, and a control valve configured to direct fluid from the pump to the actuator and from the actuator to the tank. The hydraulic control system may also have a pressure sensor to generate a first signal indicative of a pressure differential across the control valve, an operator input device to generate a second signal indicative of a desired movement of the actuator, and a controller. The controller may be configured to make a first determination of an opening amount of the control valve based on the second signal, and to make a second determination based on the first signal of whether the opening amount will result in overspeeding of the actuator. The controller may also be configured to reduce the opening amount based on the second determination.

Abstract: A hydraulic control system is disclosed for use with a machine. The hydraulic control system may have a tank, a pump, a swing motor, and at least one control valve configured to control fluid flow between the pump, the swing motor, and the tank. The hydraulic system may also have an accumulator configured to selectively receive pressurized fluid discharged from the swing motor and selectively supply pressurized fluid to the swing motor, at least one accumulator valve, and a controller. The controller may be configured to receive input indicative of a difference between desired and actual speeds of the swing motor, and determine if the swing motor is accelerating or decelerating based on the difference. The controller may also be configured to control the at least one accumulator valve to cause the accumulator to selectively receive or supply pressurized fluid only when the swing motor is accelerating or decelerating.

Abstract: A method and system for accumulating and using recovered hydraulic energy that includes a hydraulic actuator and a pump configured to supply pressurized fluid to the hydraulic actuator. An energy recovery system includes a hydraulic motor, a charge valve and an accumulator configured to store fluid from the hydraulic actuator. The charge valve is operatively connected between the hydraulic actuator and the accumulator and between the accumulator and the hydraulic motor and is configured to place the hydraulic actuator in fluid communication with the accumulator and to place the accumulator in fluid communication with the hydraulic motor. A directional valve is operatively connected between the pump and the hydraulic actuator. The directional valve is configured to place the pump in fluid communication with the hydraulic actuator and to direct the flow of hydraulic fluid exiting the hydraulic actuator to the charge valve in an energy recovery mode.

Abstract: A hydraulic system includes a variable-displacement first pump, an over-center variable-displacement first travel motor selectively connected to receive fluid pressurized by the first pump in a closed loop manner, and an over-center variable-displacement second travel motor selectively connected to receive fluid pressurized by the first pump in parallel with the first travel motor in a closed loop manner. The hydraulic system also includes a linear actuator selectively connected to receive fluid pressurized by the first pump in parallel with the first and second travel motors in a closed loop manner.

Abstract: A hydraulic system includes a variable-displacement first pump, a variable-displacement second pump, and a first actuator selectively connected either to the first pump in a closed loop manner and not the second pump, or to the first and second pumps in a closed loop manner. The hydraulic system also includes a second actuator selectively connected either to the second pump in a closed loop manner and not the first pump, or to the first and second pumps in a closed loop manner. The hydraulic system further includes a variable-displacement rotary actuator selectively connected either to the first pump in a closed loop manner and not the second pump, or to the first and second pumps in a closed loop manner.

Abstract: A hydraulic system includes a variable-displacement first pump and a variable-displacement second pump. The hydraulic system also includes a first actuator selectively connected either to the first pump in a closed loop manner and not the second pump, to the second pump in a closed loop manner and not the first pump, or to the first and second pumps in a closed loop manner. The hydraulic system further includes a second actuator and a variable-displacement rotary actuator that are each selectively connected either to the first pump in a closed loop manner and not the second pump, to the second pump in a closed loop manner and not the first pump, or to the first and second pumps in a closed loop manner.

Abstract: A system including a hydraulic accumulator, a pressure sensor, a fluid source and a data processor to detect a pre-charge pressure is provided. The hydraulic accumulator includes first and second fluid chambers and a separator therebetween. The hydraulic accumulator has an associated pre-charge pressure. The pressure sensor is connected to the first fluid chamber. The data processor is connected to the pressure sensor. The data processor is configured to determine a first and second rate of pressure changes, and a transition pressure between the first and second rates. The approximate pre-charge pressure is determined based on the transition pressure.

Abstract: A hydraulic system includes a variable-displacement first pump, a variable-displacement second pump, and a first actuator selectively connected either to the first pump in a closed loop manner and not the second pump, or to the first and second pumps in a closed loop manner. The hydraulic system also includes a second actuator selectively connected either to the second pump in a closed loop manner and not the first pump, or to the first and second pumps in a closed loop manner. The hydraulic system further includes a variable-displacement rotary actuator selectively connected either to the first pump in a closed loop manner and not the second pump, or to the first and second pumps in a closed loop manner.

Abstract: A system including a hydraulic accumulator, a pressure sensor, a fluid source and a data processor to detect a pre-charge pressure is provided. The hydraulic accumulator includes first and second fluid chambers and a separator therebetween. The hydraulic accumulator has an associated pre-charge pressure. The pressure sensor is connected to the first fluid chamber. The data processor is connected to the pressure sensor. The data processor is configured to determine a first and second rate of pressure changes, and a transition pressure between the first and second rates. The approximate pre-charge pressure is determined based on the transition pressure.

Abstract: A method and system for accumulating and using recovered hydraulic energy that includes a hydraulic actuator and a pump configured to supply pressurized fluid to the hydraulic actuator. An energy recovery system includes a hydraulic motor, a charge valve and an accumulator configured to store fluid from the hydraulic actuator. The charge valve is operatively connected between the hydraulic actuator and the accumulator and between the accumulator and the hydraulic motor and is configured to place the hydraulic actuator in fluid communication with the accumulator and to place the accumulator in fluid communication with the hydraulic motor. A directional valve is operatively connected between the pump and the hydraulic actuator. The directional valve is configured to place the pump in fluid communication with the hydraulic actuator and to direct the flow of hydraulic fluid exiting the hydraulic actuator to the charge valve in an energy recovery mode.

Abstract: A hydraulic control system is disclosed. The hydraulic control system may have an input device to generate a first signal indicative of a desired swing motor movement, and a control valve configured to selectively pass fluid to the swing motor and drain from the swing motor to drive the swing motor based on the first signal. The hydraulic control system may also have a pressure sensor to generate a second signal indicative of a swing motor pressure, a speed sensor configured to a third signal indicative of a swing motor speed, and a controller configured to make a comparison of at least one of the swing motor speed and the swing motor pressure with a threshold speed and a threshold pressure, and open the control valve to drain fluid from the swing motor to the tank based on the comparison when the input device is in a neutral condition.

Abstract: A hydraulic control system is disclosed for use with a machine. The hydraulic control system may have a tank, a pump, a swing motor, and at least one control. The hydraulic control system may further have an accumulator configured to receive fluid from and supply fluid to the swing motor, a charge valve movable to allow fluid flow from the swing motor into the accumulator, and a discharge valve movable to allow fluid flow from the accumulator to the swing motor. The hydraulic control system may additionally have a controller in communication with the at least one control valve, the charge valve, and the discharge valve. The controller may be configured to detect an acceleration of the swing motor, selectively cause the discharge valve to assist the acceleration, and selectively move the charge valve to an open position to recover energy associated with pressure spikes occurring during the acceleration.

Abstract: A hydraulic control system is disclosed for use with a machine. The hydraulic control system may have a tank, a pump, an actuator, and a control valve configured to direct fluid from the pump to the actuator and from the actuator to the tank. The hydraulic control system may also have a pressure sensor to generate a first signal indicative of a pressure differential across the control valve, an operator input device to generate a second signal indicative of a desired movement of the actuator, and a controller. The controller may be configured to make a first determination of an opening amount of the control valve based on the second signal, and to make a second determination based on the first signal of whether the opening amount will result in overspeeding of the actuator. The controller may also be configured to reduce the opening amount based on the second determination.

Abstract: A control system is disclosed for use with an excavation machine. The control system may have a work tool, an operator input device to receive input indicative of a desired movement of the work tool, at least one actuator, and at least one sensor associated with at least one of the work tool and the at least one actuator. The control system may also have a controller in communication with the operator input, the at least one actuator, and the at least one sensor. The controller may be configured to make a classification of a current operation of the machine as one of a plurality of known operations based on a signal from at least one of the operator input device and the at least one sensor. The controller may be further configured to adjust an operational parameter of the at least one actuator based on the classification.

Abstract: A hydraulic control system is disclosed for use with a machine. The hydraulic control system may have a tank, a pump, a swing motor, and at least one control valve configured to control fluid flow between the pump, the swing motor, and the tank. The hydraulic system may also have an accumulator configured to selectively receive pressurized fluid discharged from the swing motor and selectively supply pressurized fluid to the swing motor, at least one accumulator valve, and a controller. The controller may be configured to receive input indicative of a difference between desired and actual speeds of the swing motor, and determine if the swing motor is accelerating or decelerating based on the difference. The controller may also be configured to control the at least one accumulator valve to cause the accumulator to selectively receive or supply pressurized fluid only when the swing motor is accelerating or decelerating.

Abstract: A hydraulic system for a machine is disclosed. The hydraulic system may have a hydraulic actuator, and at least one valve configured to regulate fluid flows associated with the hydraulic actuator. The hydraulic system may also have an operator interface device configured to generate a position signal indicative of a desired movement velocity of the hydraulic actuator, a mode switch movable to generate a mode signal indicative of desired operation in one of a normal control mode and a fine control mode, and a controller. The controller may be configured to move the at least one valve to a first position based on the position signal when the mode signal indicates desired operation in the normal mode, and to move the at least one valve to a second position based on the position signal when the mode signal indicates desired operation in the fine control mode.

Abstract: A system to diagnose a health of a hydraulic accumulator is provided. The hydraulic accumulator includes a first fluid chamber, a second fluid chamber, and a separator. The hydraulic accumulator has an associated pre-charge pressure. The system further includes a pressure sensor, a fluid source, a data processor, and a comparator. The pressure sensor and the fluid source are connected to the first fluid chamber. The data processor is configured to determine a first and second rate of pressure changes, and a transition pressure between the first and second rates. The approximate pre-charge pressure is determined based on the transition pressure. The comparator is configured to compare at least one of the determined pre charge pressure and the frictional forces with a pre-determined threshold range of pre-charge pressure and the frictional forces associated with the hydraulic accumulator to diagnose the health of the hydraulic accumulator.