The improved hydraulic system utilizes a secondary hydraulic force control circuit that changes the gripping force on the load independently of movement of the clamp arms.

The invention relates to a hydraulic transmission unit for an actuator, which hydraulic transmission unit can be filled with a hydraulic fluid and has a first and a second chamber which are hydraulically interconnected and of which one is designed as a drive chamber and the other one is designed as an output chamber. At least in the first chamber, a piston is arranged movably along a piston axis, such that this piston subdivides the first chamber into a variable-volume working chamber and a rear-side chamber, the rear-side chamber being delimited at least partially by a bellows element having a variable axial length. The invention further relates to an actuator having such a hydraulic transmission unit.

A hydraulic machine unit that can be operated with various working forces, in which working medium is selectively delivered, via a pump-piston accumulator system, to a main cylinder and at least one driving cylinder, wherein at least for one working stroke a pump system of the pump-piston accumulator system is used to provide working medium to a piston accumulator of the pump-piston accumulator system, and then at least for the working stroke at least the main cylinder is charged with a working pressure from the piston accumulator, and wherein at least for a return stroke the at least one driving cylinder is charged with a return stroke pressure from the pump-piston accumulator system, can be of structurally simple configuration if, at reduced working forces, the working pressure is reduced with respect to the piston accumulator pressure prevailing in the piston accumulator.

The present disclosure relates to variable recruitment actuator systems and related methods. In one embodiment, a variable recruitment actuator system may include a high-pressure fluid connection and a plurality of actuators. A variable recruitment actuator mechanism may selectively recruit a subset of the plurality of actuators based on a position of the variable recruitment actuator mechanism by selectively placing the subset of the plurality of actuators in fluid communication with the high-pressure fluid connection. A control system to control the position of the variable recruitment actuator mechanism may operate based on an input from a user.

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 hydraulic system has two hydraulic circuits, each with a pressure generating unit acting on an actuator unit. The generating units are slot-controlled radial piston pumps and form a pump assembly with a single common pump support and single common rotor. The rotor is rotatable on a free protruding section of a common support hub and has piston-receiving bores on axially offset planes. The hub has two first and two second fluid bores. The first bores communicate with first pump connections and first control openings on the hub on a first plane, and the second fluid bores communicate with second pump connections and second control openings on the hub on a second plane. A first and a second adjustment frame, each having an eccentric ring and acting on the pump pistons, are disposed on respective planes perpendicular to the main axis and independently guided in a linearly movable manner.

Provided is a fluid actuator capable of safely driving a drive target. An air actuator using air as a working fluid includes an X-axis pressure sensor that measures air pressures PX+ and PX− along one drive axis, which drives a drive target in an X direction, a Y-axis pressure sensor that measures air pressures PY1+, PY1−, PY2+, and PY2− along two drive axes, which drive the drive target in a Y direction, and an acceleration detection unit that detects translational acceleration and rotational acceleration generated in the drive target on the basis of the measured air pressures PX+, PX−, PY1+, PY1−, PY2+, and PY2−.

A method controls the movement of a boom, wherein the boom is moved by a plurality of hydraulic drives. Each hydraulic drive is fed with a hydraulic medium, the pressure and/or volume flow of which is adjustable. The method predefines a desired direction of movement and a desired speed of a boom tip; predictively calculates a pressure and/or a volume flow required for each of the hydraulic drives that are required for the desired direction of movement and desired speed; subsequently generates a supply pressure depending on the predictively calculated pressures and/or subsequently generating a supply volume flow as a function of the predictively calculated volume flows; and subsequently feeds the hydraulic drives required for the desired direction of movement and desired speed with the hydraulic medium having a respective feed pressure and/or a respective feed volume flow such that the boom tip moves in the desired direction of movement at the desired speed.

Control surface actuator assemblies, aircraft hydraulic systems including the same, and associated aircraft and methods. A control surface actuator assembly includes a flight control surface operatively coupled to a support structure, a torque-generating hydraulic actuator configured to apply a torque to pivot the flight control surface, and a variable horn radius (VHR) hydraulic actuator configured to vary an actuator moment arm length for pivoting the flight control surface. In some examples, an aircraft hydraulic system includes such control surface actuator assemblies, and an aircraft includes such aircraft hydraulic systems. In some examples, a method of operating one or more flight control surfaces of an aircraft includes controlling a selected flight control surface by adjusting, with a VHR hydraulic actuator, an actuator moment arm length corresponding to the selected flight control surface and pivoting, with a torque-generating hydraulic actuator, the selected flight control surface.

Provided is a fluid actuator capable of safely driving a drive target. An air actuator using air as a working fluid includes an X-axis pressure sensor that measures air pressures PX+ and PX− along one drive axis, which drives a drive target in an X direction, a Y-axis pressure sensor that measures air pressures PY1+, PY1−, PY2+, and PY2− along two drive axes, which drive the drive target in a Y direction, and an acceleration detection unit that detects translational acceleration and rotational acceleration generated in the drive target on the basis of the measured air pressures PX+, PX−, PY1+, PY1−, PY2+, and PY2−.