A hoist valve assembly for a work machine cylinder includes a main control valve, a counterbalance valve and a counterbalance shutoff valve. A main control valve raise position connects a head end of the cylinder with a pressurized fluid source and a rod end of the cylinder to a low pressure reservoir to extend the cylinder. The counterbalance valve is between the rod end and the main control valve, is biased to a closed position and has an open position connecting the rod end to the low pressure reservoir. Rod end and head end pressure signals apply force to the counterbalance valve toward the open position. The counterbalance shutoff valve is positioned between the head end and the counterbalance valve, and has a normal position to apply the head end pressure signal to the counterbalance valve and a shutoff position that blocks the head end pressure signal from the counterbalance valve.

A counter pressure valve arrangement for controlling a pressure level of a hydraulic fluid in a return line from a hydraulic actuator arrangement. The counter pressure valve arrangement comprises a counter pressure valve having: a moveable valve member; a counter pressure regulating port configured for being connected to the hydraulic actuator arrangement via the return line; a tank port configured for being connected to a tank or low pressure reservoir for storing low pressure hydraulic fluid; and a pump port configured for being connected to a source of pressurised hydraulic fluid. A first position of the valve member effects fluid communication between the pump port and the counter pressure regulating port for supplying pressurised hydraulic fluid to the return line, and a second position of the valve member effects fluid communication between the counter pressure regulating port and the tank port for discharging hydraulic fluid from the return line to the tank.

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.

Provided is an arrangement and a method to detect an oil leakage between a first section and a second section of a hydraulic cylinder. A movable piston is arranged between the first and second section in a way that the piston changes position between the sections. The change in position is done in dependency of a difference between a first force, which acts at the first section on a first cross sectional area of the piston, and a second force, which acts at the second section on a second cross sectional area of the piston. The first section comprises hydraulic oil with a predefined first pressure, while the first force is calculated based on this pressure and based on the first area. The second section comprises hydraulic oil with a predefined second pressure, while the second force is calculated based on this pressure and based on the second area.

In the disclosed solution, a boom assembly (14) of a work machine (1) is controlled by tip control. In tip control, a control command is given to a tip of a boom assembly (14), converted into control commands for individual actuators of the boom assembly (14). In the disclosed solution, a variable related to a load and its position at the tip of the boom assembly (14) is defined, and the variable in question related to the load and its position at the tip of the boom assembly (14) is taken into account in the control command for the actuator.

The invention relates to a method for monitoring operating parameters of an actuator (10), wherein the method comprises: providing the actuator (10), providing at least two detection units (26, 28, 30, 32, 34, 36) which are designed to detect different operating parameters of the actuator (10), detecting operating parameters of the actuator (10) via the detection units (26, 28, 30, 32, 34, 36), outputting data relating to the measured operating parameters to an evaluation unit, combining the measured operating parameters into a state information, which indicates whether or not the technical state of the actuator (10) is in a predetermined standard state.

A process valve apparatus (10), including: a process fitting (1) with a valve member (2), a pneumatic valve drive (3) for actuating the valve member (2), and a control device (4) with a pneumatic valve device (5) for pneumatically actuating the valve drive (3), wherein the control device (4) is configured to carry out a partial stroke test and, within the partial stroke test: to actuate the valve drive (3) pneumatically by means of the valve device (5), so that the valve drive (3) sets the valve member (2) in a test movement sequence in which the valve member (2) performs a first test movement from a first position (x1) to a second position (x2) and a second test movement from the second position (x2) back to the first position (x1), to detect pressure information related to the pneumatic actuation of the valve drive (3) and, taking into account the pressure information, to determine status information indicating the functioning and/or the wear of the process valve apparatus (10).

A hydraulic rotary drive includes a first rotary drive element and at least two annular pistons connected to the first rotary drive element in a rotationally fixed manner and configured to be axially movable on the first rotary drive element between two end positions. Each annular piston has two annular spur serrations directed away from one another. The hydraulic rotary drive includes a second rotary drive element with ring type serrations that are complementary to the spur serrations of the annular pistons. The hydraulic rotary drive includes a control unit that is configured to control supply of hydraulic fluid to the annular pistons to cause a reciprocating movement of the annular pistons on a shaft in accordance with an operating signal. The hydraulic rotary drive includes a sensor arrangement communicatively coupled to the control unit and arranged to detect the positions of the annular pistons along respective sliding paths.

A method for operating a fluid system including the steps: receiving or determining a set value for a stroke of the working valve, determining an actual value for the stroke of the working valve using a sensor signal of a position sensor, determining a deviation value of a working valve in dependence on sensor signals of a supply pressure sensor and a working pressure sensor and a position sensor and a sensor system, and performing a processing of the set value for the stroke of the working valve, the actual value for the stroke of the working valve and the deviation value to a control signal for driving the working valve.

A method is for controlling an actuation force exerted by an actuating device having a first working chamber and a second working chamber supplied with pressurized air from a source of pressurized air by a first pressure regulator and a second pressure regulator. The method includes calculating, by an optimization algorithm based on a dynamic model of the actuating device and of the first and second pressure regulators, desired values for control signals for the first and second pressure regulators to generate an actuation force equal to a desired value for the actuation force. An estimated value for the actuation force, estimated values for pressures inside the first and second working chambers and for first derivatives of the pressures, are determined by a state observer based on a measured value for the actuation force and on measured values for the pressures in the first and second working chambers.