Abstract: A system and method for the controlled lowering and lifting of a load are disclosed. The system and method may include operating a work machine having a hydraulic system including a hydraulic actuator for supporting a load, a first control valve in fluid communication with the actuator, and a controller for operating the first control valve. In one embodiment, the controller includes a first algorithm for operating the first control valve in a load lowering operation. When an operational fault within the hydraulic system is detected, the controller can be configured to enter into a safe lowering mode. In the safe lowering mode, the first algorithm is disabled and a pulse width modulation (PWM) current is sent from the controller to the first control valve. A user interface is provided to allow an operator to control the PWM current duty ratio to allow the load supported by the actuator to be lowered.

Abstract: A system and method for the controlled lowering and lifting of a load are disclosed. The system and method may include operating a work machine having a hydraulic system including a hydraulic actuator for supporting a load, a first control valve in fluid communication with the actuator, and a controller for operating the first control valve. In one embodiment, the controller includes a first algorithm for operating the first control valve in a load lowering operation. When an operational fault within the hydraulic system is detected, the controller can be configured to enter into a safe lowering mode. In the safe lowering mode, the first algorithm is disabled and a pulse width modulation (PWM) current is sent from the controller to the first control valve. A user interface is provided to allow an operator to control the PWM current duty ratio to allow the load supported by the actuator to be lowered.

Abstract: A system and method for the controlled lowering and lifting of a load are disclosed. The system and method may include operating a work machine having a hydraulic system including a hydraulic actuator for supporting a load, a first control valve in fluid communication with the actuator, and a controller for operating the first control valve. In one embodiment, the controller includes a first algorithm for operating the first control valve in a load lowering operation. When an operational fault within the hydraulic system is detected, the controller can be configured to enter into a safe lowering mode. In the safe lowering mode, the first algorithm is disabled and a pulse width modulation (PWM) current is sent from the controller to the first control valve. A user interface is provided to allow an operator to control the PWM current duty ratio to allow the load supported by the actuator to be lowered.

Abstract: A system and method for the controlled lowering and lifting of a load are disclosed. The system and method may include operating a work machine having a hydraulic system including a hydraulic actuator for supporting a load, a first control valve in fluid communication with the actuator, and a controller for operating the first control valve. In one embodiment, the controller includes a first algorithm for operating the first control valve in a load lowering operation. When an operational fault within the hydraulic system is detected, the controller can be configured to enter into a safe lowering mode. In the safe lowering mode, the first algorithm is disabled and a pulse width modulation (PWM) current is sent from the controller to the first control valve. A user interface is provided to allow an operator to control the PWM current duty ratio to allow the load supported by the actuator to be lowered.

Abstract: A system and method for the controlled lowering and lifting of a load are disclosed. The system and method may include operating a work machine having a hydraulic system including a hydraulic actuator for supporting a load, a first control valve in fluid communication with the actuator, and a controller for operating the first control valve. In one embodiment, the controller includes a first algorithm for operating the first control valve in a load lowering operation. When an operational fault within the hydraulic system is detected, the controller can be configured to enter into a safe lowering mode. In the safe lowering mode, the first algorithm is disabled and a pulse width modulation (PWM) current is sent from the controller to the first control valve. A user interface is provided to allow an operator to control the PWM current duty ratio to allow the load supported by the actuator to be lowered.

Abstract: A control system for a hydraulic system including an accumulator and a hydraulic transformer coordinates flow sharing within the hydraulic system. The hydraulic transformer includes first and second variable displacement pump/motor units mounted on a rotatable shaft. The rotatable shaft has an end adapted for connection to a first external load. The first variable displacement pump/motor unit includes a first side that fluidly connects to a pump and a second side that fluidly connects to a tank. The second variable displacement pump/motor unit includes a first side that fluidly connects to the accumulator and a second side that fluidly connects with the tank. A second external load may be hydraulically connected to the hydraulic system. Energy may be transferred to/from the pump, the accumulator, the first external load, and/or the second external load, as directed by the control system.

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: A control system for a hydraulic system including an accumulator and a hydraulic transformer coordinates flow sharing within the hydraulic system. The hydraulic transformer includes first and second variable displacement pump/motor units mounted on a rotatable shaft. The rotatable shaft has an end adapted for connection to a first external load. The first variable displacement pump/motor unit includes a first side that fluidly connects to a pump and a second side that fluidly connects to a tank. The second variable displacement pump/motor unit includes a first side that fluidly connects to the accumulator and a second side that fluidly connects with the tank. A second external load may be hydraulically connected to the hydraulic system. Energy may be transferred to/from the pump, the accumulator, the first external load, and/or the second external load, as directed by the control system.

Abstract: To achieve flow demands for high flow services, a hydraulic system shares a flow between a hydraulic transformer and one or more hydraulic pumps. The hydraulic transformer is in selective fluid communication with the pumps and actuates a first load. A second load is driven by an actuator in selective fluid communication with the pumps and the hydraulic transformer. The hydraulic system includes a controller to reduce dynamic responses in the system by causing flow sharing between the hydraulic transformer and a directional flow control valve.

Abstract: To achieve flow demands for high flow services, a hydraulic system shares a flow between a hydraulic transformer and one or more hydraulic pumps. The hydraulic transformer is in selective fluid communication with the pumps and actuates a first load. A second load is driven by an actuator in selective fluid communication with the pumps and the hydraulic transformer. The hydraulic system includes a controller to reduce dynamic responses in the system by causing flow sharing between the hydraulic transformer and a directional flow control valve.

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: A system and method for the controlled lowering and lifting of a load are disclosed. The system and method may include operating a work machine having a hydraulic system including a hydraulic actuator for supporting a load, a first control valve in fluid communication with the actuator, and a controller for operating the first control valve. In one embodiment, the controller includes a first algorithm for operating the first control valve in a load lowering operation. When an operational fault within the hydraulic system is detected, the controller can be configured to enter into a safe lowering mode. In the safe lowering mode, the first algorithm is disabled and a pulse width modulation (PWM) current is sent from the controller to the first control valve. A user interface is provided to allow an operator to control the PWM current duty ratio to allow the load supported by the actuator to be lowered.