A hydraulic system includes a hydraulic valve, a load-holding valve arrangement, a flow-control valve arrangement, a working pressure sensor, a differential pressure sensor, and a speed sensor. The load-holding valve arrangement includes first and second load-holding valves connected to opposite ends of the hydraulic cylinder. The flow-control valve arrangement includes a directional flow-control valve and a hydraulic pump. The differential pressure sensor measures pressure over the load-holding valve arrangement. A desired extension or retraction speed of the hydraulic cylinder is controlled by adjusting the position of the directional flow-control valve, the first load-holding valve and the second load-holding valve based on a measured working pressure in the hydraulic system and a measured speed of the hydraulic cylinder or a differential pressure over the load-holding valve arrangement.

An electric-powered fail-safe actuator for use with a valve, where the actuator stores potential energy for conversion to kinetic energy to close or open the valve to the fail-safe position.

An actuator controller for actuating an actuator which can be operated fluidically, having a feed line for an inflow of the working fluid to an actuator connector and having a discharge line for an outflow of the working fluid to a fluid outlet, wherein the feed line is assigned a feed line valve and the discharge line is assigned a discharge valve, which valves are configured in each case to influence a volumetric fluid flow at the actuator connector, and having a control device for actuation of the feed line valve and the discharge valve. A throughflow sensor is arranged in a line section between the discharge valve and the fluid outlet, which throughflow sensor is configured for determining a volumetric fluid flow in the discharge line and for providing a throughflow signal.

An example robot includes a hydraulic actuator cylinder controlling motion of a member of the robot. The hydraulic actuator cylinder comprises a piston, a first chamber, and a second chamber. A valve system controls hydraulic fluid flow between a hydraulic supply line of pressurized hydraulic fluid, the first and second chambers, and a return line. A controller may provide a first signal to the valve system so as to begin moving the piston based on a trajectory comprising moving in a forward direction, stopping, and moving in a reverse direction. The controller may provide a second signal to the valve system so as to cause the piston to override the trajectory as it moves in the forward direction and stop at a given position, and then provide a third signal to the valve system so as to resume moving the piston in the reverse direction based on the trajectory.

A first flow path area at a position where one of multiple openings of a sleeve and one of multiple grooves of a spool overlap with each other is different in size from a second flow path area at a position where another one of the openings of the sleeve and another one of the grooves of the spool overlap with each other. The one opening and the one groove form a flow path for connecting one of one pressure chamber and the other pressure chamber to a fluid supply source, due to displacement of the spool. The other opening and the other groove form a flow path for connecting another one of the other pressure chamber and the one pressure chamber to a fluid discharge port, due to the displacement of the spool.

In a fluid circuit for an air cylinder connected to a switching valve provided with exhaust ports, a head-side pressure chamber is connected to the switching valve by a first pipe, and a rod-side pressure chamber is connected to the switching valve by a second pipe. A first restrictor is disposed at a connection point between the first pipe and the switching valve or in the vicinity of a first output port of the switching valve, and a second restrictor is disposed at a connection point between the second pipe and the switching valve or in the vicinity of a second output port of the switching valve.

The present disclosure relates to a hydraulic control circuit for crane slewing gear having directional valves arranged in work lines and controllable separately for the inflow and outflow to the hydraulic motor for the carrying out of a rotational movement of the slewing gear, wherein an inflow valve serves the control of the oil inflow from a hydraulic pump via the work line to the hydraulic motor and an outflow valve is provided via which the hydraulic motor can be relieved to the tank, wherein the work lines are each connected via at least one check valve to a common inlet of the outflow valve to relieve the hydraulic motor independently of the direction of rotation of the slewing gear via an outflow valve into the tank.

An object of the present invention is to provide a construction machine that allows easy and accurate calibration of a pressure sensor and enables accurate control of hydraulic actuators. A controller increases the delivery pressure of a hydraulic pump in a state in which first and second meter-out valves and a second meter-in valve are closed and in which a first meter-in valve is opened, and calibrates a first pressure-calculation map such that a pressure calculated on the basis of the first pressure-calculation map matches a pressure calculated on the basis of a supply-pressure-calculation map, and increases the delivery pressure of the hydraulic pump in a state in which the first and second meter-out valves and the first meter-in valve are closed and in which the second meter-in valve is opened, and calibrates a second pressure-calculation map such that a pressure calculated on the basis of the second pressure-calculation map matches the pressure calculated on the basis of the supply-pressure-calculation map.

A control system and method for controlling the positioning of an adjustable deflector plate employed in a harvesting combine to adjust a side-to-side flow of crop residue to spreaders associated with the combine and the distribution thereby. The deflector plate is operably extendable into the flow of crop residue to redirect crop residue impinging the deflector plate. The deflector plate is adjusted based upon a comparison between the open/closed states of valves associated with the control system.

Provided is a work machine which can increase the operation speed of an actuator by a regeneration function while securing the position control accuracy of the actuator. A controller is configured to calculate a regeneration flow rate on the basis of an input amount of an operation lever and a target actuator flow rate, subtract the regeneration flow rate from the target actuator flow rate to calculate a target actuator supply flow rate, calculate a target flow rate control valve opening amount on the basis of the target actuator supply flow rate, calculate a target pump flow rate that is equal to or higher than a total target actuator supply flow rate, control a selector valve on the basis of the input amount of the operation lever, control a flow rate control valve according to the target flow rate control valve opening amount, and control a hydraulic pump according to the target pump flow rate.