The electro-hydrostatic actuator system for raising and lowering aircraft landing gear (1) is provided with at least one hydraulic actuator (21, 22) that is constituted so as to perform retraction and deployment of landing gear (11), a hydraulic circuit (33), a hydraulic pump (32), an electric motor (31), a controller (4) constituted so as to control the operation of the electric motor upon receiving an instruction relating to retraction of the landing gear or an instruction relating to deployment of the landing gear, and a sensor (34) that detects the discharge pressure of the hydraulic pump. The controller feeds back the discharge pressure that the sensor has detected, and controls the operation of the electric motor so that the discharge pressure of the hydraulic pump becomes a target discharge pressure.

The electro-hydrostatic actuator system for raising and lowering aircraft landing gear (1) is provided with at least one hydraulic actuator (21, 22) that is constituted so as to perform retraction and deployment of landing gear (11), a hydraulic circuit (33), a hydraulic pump (32), an electric motor (31), a controller (4) constituted so as to control the operation of the electric motor upon receiving an instruction relating to retraction of the landing gear or an instruction relating to deployment of the landing gear, and a sensor (34) that detects the discharge pressure of the hydraulic pump. The controller feeds back the discharge pressure that the sensor has detected, and controls the operation of the electric motor so that the discharge pressure of the hydraulic pump becomes a target discharge pressure.

A method actuates a hydraulic system for an actuation device of a motor vehicle. The hydraulic system has a pump and multiple valves which are each arranged between a system rail connected to a pump outlet and a hydraulic consumer. The pump is switched between a normal operation and an enhanced operation according to an existing total energy demand of the hydraulic consumers. In normal operation, the pump is driven when the system pressure is below a lower pressure threshold and switched off when the system pressure is above an upper pressure threshold. In the enhanced operation, the pump is permanently driven and each of the valves is operated according to an individual energy demand of the respective hydraulic consumer as soon as the system pressure achieves or exceeds a threshold value.

A method actuates a hydraulic system for an actuation device of a motor vehicle. The hydraulic system has a pump and multiple valves which are each arranged between a system rail connected to a pump outlet and a hydraulic consumer. The pump is switched between a normal operation and an enhanced operation according to an existing total energy demand of the hydraulic consumers. In normal operation, the pump is driven when the system pressure is below a lower pressure threshold and switched off when the system pressure is above an upper pressure threshold. In the enhanced operation, the pump is permanently driven and each of the valves is operated according to an individual energy demand of the respective hydraulic consumer as soon as the system pressure achieves or exceeds a threshold value.

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.

A fluid control system for supplying fluid to a fluid consumer, having a valve module including a channel body to which a fluid switching valve, a fluid pressure regulator and a vacuum switching valve are attached, the channel body having a first fluid channel extending from a fluid input port to an input port of the fluid pressure regulator and having a second fluid channel extending from an output port of the fluid pressure regulator to an input port of the fluid switching valve, and having a third fluid channel extending from an output port of the fluid switching valve to a fluid consumer port, and having a first vacuum channel extending from a vacuum input port to an input port of the vacuum switching valve, and having a second vacuum channel extending from an output port of the vacuum switching valve to the fluid consumer port.

A system and method is provided for monitoring a hydraulic power system having at least one light emitter and a button. The method includes powering on the hydraulic power system, receiving an actuation at the button and detecting a release of the button after a first time interval, and entering a diagnostic state. The method further includes retrieving a code and displaying the code by turning on the emitter in a first pattern. In some embodiments, a system and method is provided for regulating a temperature of a hydraulic power system. In some embodiments, a system and method is provided for controlling operation of a hydraulic torque wrench.

A system and method is provided for monitoring a hydraulic power system having at least one light emitter and a button. The method includes powering on the hydraulic power system, receiving an actuation at the button and detecting a release of the button after a first time interval, and entering a diagnostic state. The method further includes retrieving a code and displaying the code by turning on the emitter in a first pattern. In some embodiments, a system and method is provided for regulating a temperature of a hydraulic power system. In some embodiments, a system and method is provided for controlling operation of a hydraulic torque wrench.

A coupler cylinder is driven between a locked state and an unlocked state of a bucket by being supplied with hydraulic oil. A main pump supplies the hydraulic oil to the coupler cylinder. A pressure increasing valve controls the supply of the hydraulic oil to the coupler cylinder. A controller controls drive of the pressure increasing valve. The controller instructs the pressure increasing valve to stop the supply of the hydraulic oil to the coupler cylinder based on pressure in an oil passage between the main pump and the coupler cylinder.

It is an object of the present invention to provide a construction machine capable of efficiently driving a hydraulic cylinder by an accumulator. Thus, the construction machine includes a first control valve disposed in a first hydraulic fluid line connecting a bottom-side fluid chamber of a hydraulic cylinder with an accumulator, and a second control valve disposed in a second hydraulic fluid line connecting a rod-side fluid chamber of the hydraulic cylinder with a tank. The construction machine further includes a third control valve disposed in a third hydraulic fluid line connecting the rod-side fluid chamber with the accumulator, and a fourth control valve disposed in a fourth hydraulic fluid line connecting a line part of the first hydraulic fluid line, which connects the bottom-side fluid chamber with the third control valve, and a line part of the third hydraulic fluid line, which connects the rod-side fluid chamber with the third control valve, with each other.