A milling machine has a frame, ground engaging tracks that support the frame, a first actuator connecting the frame to a first track of the ground engaging tracks and a second actuator connecting the frame to a second track from the ground engaging tracks. The milling machine has an orientation sensor that determines an orientation of the frame. The milling machine has a controller that operates the first and second actuators to raise or lower the frame. The controller determines the frame orientation using the orientation sensor. The controller also determines a velocity error between actuator velocities of the first and second actuators based on the frame orientation and a target orientation of the frame. The controller determines a control parameter for the second actuator based on the velocity error and operates the second actuator using the determined control parameter.

A high-pressure unit (HPU) skid for greasing and actuating a frac tree valve includes one or more hydraulic pumps, a grease pump, a hydraulic reservoir, and two or more accumulators all of which are mounted on a portable frame. The HPU skid further includes fluidic connections to connect the frac tree valve to an output of the grease pump and fluidic connections to connect the frac tree valve to at least one of the two or more accumulators. The hydraulic pumps are configured to withdraw hydraulic fluid from the hydraulic reservoir for charging the accumulators, operating the grease pump, or charging the accumulators and operating the grease pump at a same time.

A system has a hydraulic circuit configured to control a position of an attachment of the system and a control system configured to perform operations that include receiving an input indicative of a center of gravity of the attachment and controlling a flow rate of fluid directed through the hydraulic circuit based on the center of gravity.

A hydraulic fluid pressure amplifier system includes a boost cylinder assembly, an energy storage device in fluid communication with the boost cylinder assembly, and a working cylinder assembly. The boost cylinder assembly includes a boost cylinder and a boost cylinder piston movable relative to the boost cylinder between a retracted position and an extended position, wherein movement of the boost cylinder piston from the retraced position to the extended position compresses a hydraulic fluid in a blind side volume of the boost cylinder from a nominal fluid pressure to an amplified high fluid pressure greater than the nominal fluid pressure. The energy storage device receives the hydraulic fluid compressed from the nominal fluid pressure to the amplified high fluid pressure. The working cylinder assembly is operatively connected with the boost cylinder assembly and is selectively operable for effecting the movement of the boost cylinder piston.

This invention relates to an automatic vehicle wash apparatus employing one or more rotary cloth or foam rubber brushes, and more particularly to the way how the rotary brush to vehicle surface contact is managed using one or more encoders connected to the rotating shaft of each brush and one or more programmable logic controllers (PLC). The encoders, recording the revolutions per minute (RPM) of each brush shaft, provide input to the programmable logic controller. If the RPM value is at or above the high RPM limit, the pivoted boom will move the brush toward the vehicle to achieve a desired brush-to-washable surface contact. If, on the other hand, the RPM value is at or below the low RPM limit, the pivoted boom will move the brush away from the vehicle to achieve a desired brush-to-washable surface contact.

A tail-rotor vibration dampener system for an aircraft is provided. The system includes a fuselage and an open rotor assembly including a powerplant and a set of rotor blades. The system further includes at least one actuator unit connecting the open rotor assembly to the fuselage. The actuator unit includes a hydraulic actuator controlling a position of the open rotor assembly in relation to the fuselage and a dampening device operable to cancel a vibration emanating from the open rotor assembly. The system further includes a computerized vibration dampening controller, including programming to determine a frequency of the vibration emanating from the open rotor assembly and control the dampening device to cancel the vibration emanating from the open rotor assembly based upon the frequency.

A control device for providing a position controller mode for closed-loop position control of an actuator member of a fluidic actuator which can be driven by a pressurized fluid, wherein the control device is configured to activate a pressure controller mode in response to the actuator member being located in a position target range given by a target position value of the closed-loop position control, and, in the pressure controller mode, to carry out a closed-loop pressure control of the pressurized fluid on the basis of a target pressure value.

A hydraulic leak detection system includes a leak detection switch responsive to a level of hydraulic fluid in a tank used by a hydraulic mowing circuit and a lift and lower circuit of a grass mowing machine. The system includes a controller that activates a warning indicator if the leak detection switch indicates the level of hydraulic fluid in the tank is low, but allows the hydraulic mowing circuit and the lift and lower circuit to continue operating until the lift and lower circuit reaches a fully raised position. A solenoid valve may control the level of hydraulic fluid in the tank based on temperature of the hydraulic fluid.

Working equipment including a hydraulically movable arm arrangement for a crane, an electric motor, a hydraulic pump, and a pump controller. An equipment controller is arranged to determine a maximum flow limit from the pump in dependence of a comparison of a current limit received from a battery system and a current consumption monitored by the pump controller, and to compare the determined limit with required flow of hydraulic fluid from the pump needed to move the movable arm arrangement in accordance with operating signals, and if the result does not fulfil a rule of a set of fluid control rules, the controller adapts the operating signals to reduce flow of hydraulic fluid to at least one of a plurality of actuators according to a rule of a set of adaptation rules, such that at least one rule of the set of fluid control rules is fulfilled.

A high-pressure unit (HPU) skid for greasing and actuating a frac tree valve includes one or more hydraulic pumps, a grease pump, a hydraulic reservoir, and two or more accumulators all of which are mounted on a portable frame. The HPU skid further includes fluidic connections to connect the frac tree valve to an output of the grease pump and fluidic connections to connect the frac tree valve to at least one of the two or more accumulators. The hydraulic pumps are configured to withdraw hydraulic fluid from the hydraulic reservoir for charging the accumulators, operating the grease pump, or charging the accumulators and operating the grease pump at a same time.