An actuation pressure to actuate one or more hydraulic actuators may be determined based on a load on the one or more hydraulic actuators of a robotic device. Based on the determined actuation pressure, a pressure rail from among a set of pressure rails at respective pressures may be selected. One or more valves may connect the selected pressure rail to a metering valve. The hydraulic drive system may operate in a discrete mode in which the metering valve opens such that hydraulic fluid flows from the selected pressure rail through the metering valve to the one or more hydraulic actuators at approximately the supply pressure. Responsive to a control state of the robotic device, the hydraulic drive system may operate in a continuous mode in which the metering valve throttles the hydraulic fluid such that the supply pressure is reduced to the determined actuation pressure.

A gas-pressure-driven apparatus includes a main body having a working chamber, a movable member moving relative to the main body with a pressure of the working chamber, a pressure sensor for detecting the pressure, a flow rate sensor for detecting the flow rate of the working gas. A method for controlling the apparatus includes calculating a pressure change amount from the detected pressure and an integrated flow rate from the detected flow rate when the pressure is changed in a state in which the volume of the working chamber cannot be changed, calculating an initial volume of the working chamber from the pressure change amount and the integrated flow rate, and calculating a post-change volume of the working chamber from the integrated flow rate and the initial volume after creation of a state in which the volume of the working chamber can be changed from the initial volume.

A position control system for an implement of a work vehicle. The implement, such as a blade, is operatively connected to a push arm rotatably coupled to a frame of the work vehicle. A hydraulic actuator is operatively connected to the push arm and is configured to adjust the position of the push arm with respect to the frame. A controller generates a control command to adjust the position of the hydraulic actuator to thereby raise and lower the blade. A proportional quick drop valve, coupled to the hydraulic actuator and to the controller, directs a flow of fluid to the hydraulic actuator in response to the operator control command. The proportional quick drop valve reduces a drop speed of the blade, reduces cavitation of the actuator valves, and also reduces the pressure drop and fluid flow forces acting on the spools of the actuator valves.

An actuation pressure to actuate one or more hydraulic actuators may be determined based on a load on the one or more hydraulic actuators of a robotic device. Based on the determined actuation pressure, a pressure rail from among a set of pressure rails at respective pressures may be selected. One or more valves may connect the selected pressure rail to a metering valve. The hydraulic drive system may operate in a discrete mode in which the metering valve opens such that hydraulic fluid flows from the selected pressure rail through the metering valve to the one or more hydraulic actuators at approximately the supply pressure. Responsive to a control state of the robotic device, the hydraulic drive system may operate in a continuous mode in which the metering valve throttles the hydraulic fluid such that the supply pressure is reduced to the determined actuation pressure.

A lifting control device includes: a position acquisition portion configured to acquire an extended or contracted position of the hydraulic cylinder; a target setting portion configured to set a target position of the hydraulic cylinder; a control portion configured to control an energized amount of the solenoid valve; and an input judging portion configured to judge whether the operational input is an opening command to perform an opening control in which the solenoid valve is made to be fully open or is a positional control command to perform a positional control in which the solenoid valve is actuated according to an operation input amount to control the extended or contracted position of the hydraulic cylinder, wherein when the operational input is judged as the opening command by the input judging portion, the opening control is performed due to the non-integral type control by the control portion.

A hydraulic working occupation apparatus includes: a hydraulic forming mechanism; an output element; a ball elbow mechanism connected to the hydraulic forming mechanism; and an occupation piston sleeve (25) connected to the ball elbow mechanism, wherein when a high pressure liquid is input, the high pressure liquid acts on the output element, so that the output element moves towards outside of the liquid, thereby outputting work done by liquid pressure; the ball elbow mechanism generating the location deformation drives the occupation piston sleeve (25) to move, so that the occupation piston sleeve (25) and a liquid therein make up for a liquid space left by the output element after the output element moves outwards, and when the output element moves back into the liquid, the ball elbow mechanism and the occupation piston sleeve (25) return to original locations. By using the occupation apparatus, when a working piston works towards outside of a liquid under the effect of hydraulic pressure, an occupation piston sleeve (25) and a liquid therein can occupy a liquid-off space of the piston in time, to ensure that the high liquid level does not rise and fall or the pressure of the high hydraulic pressure does not change, thereby avoiding unstable working and wastes of high pressure liquids.

The present disclosure relates to a method, a device, and a system for controlling a hydraulic pump of a construction machine, the system comprising: an engine; an engine control unit configured to control the engine by using engine limit torque information and current engine torque information of the engine; a hydraulic pump operated by power supplied from the engine; at least one actuator driven by a hydraulic pressure discharged from the hydraulic pump; and a hydraulic pump control device configured to control a limited swash plate angle of the hydraulic pump by using a torque of the hydraulic pump and the engine limit torque information received from the engine control unit.

A hydraulic system with a hydraulic power pack is disclosed having a hydraulic pump, an electric motor arranged to drive the hydraulic pump, and one or more valves connected to the hydraulic pump and arranged to directly manage, by way of direct connections and respective actuators. The hydraulic system also has a hydraulic process computer arranged to control the one or more actuators by way of the valves. An operation method of the system is also disclosed.

A servo actuator is provided which may comprise a controller configured to control a plurality of solenoid valves based upon an output signal. The plurality of solenoid valves may be used to control the position of the object. For example, a set of solenoid valves, of the plurality of solenoid valves, may be configured to conduct fluid from a tank into a first chamber of the cylinder, conduct fluid from the tank into a second chamber of the cylinder, conduct fluid from the second chamber of the cylinder into a first solenoid valve and/or conduct fluid from the first chamber of the cylinder into the first solenoid valve. The first solenoid valve, of the plurality of solenoid valves, may be configured to conduct fluid from the set of solenoid valves into a vent valve based upon a pulse width modulation (PWM) signal received from the controller.

A rephasing system may include a first hydraulic cylinder, a second hydraulic cylinder, a first rephasing valve, a second rephasing valve and a controller. The first hydraulic cylinder and the second hydraulic cylinder first and second pistons, respectively. A first hydraulic fluid line connects a hydraulic supply to a first side of the first piston while a second hydraulic fluid line connects a second side of the first piston to a first side of the second piston. The first rephasing valve fluidly couples the first side of the first piston to the first side of the second piston while the second hydraulic fluid line fluidly couples the second side of the second piston to the hydraulic supply. The controller selectively opens and closes the first and second rephasing valves to re-phase the first and second pistons.