A hydraulic system includes an engine; at least one hydraulic pump operatively coupled to the engine for transfer of mechanical power therebetween; and a controller operatively coupled to the engine and the at least one hydraulic pump. The controller is configured to determine a lug speed error as a difference between a target lug speed value and a speed of the engine, set at least one closed-loop gain to a non-zero value when the speed of the engine is less than the target lug speed value, and generate a pump control signal by scaling the lug speed error by the at least one closed-loop gain.

An indirect hydraulic load hierarchical control system and method for a wave energy device includes a first hydraulic cylinder group, a second hydraulic cylinder group, a third hydraulic cylinder group, a high-pressure energy accumulator group, a pressure detection control module, a first hydraulic power generator set, a second hydraulic power generator set and a third hydraulic power generator set. A detection end of the pressure detection control module is used for acquiring an internal pressure of the high-pressure energy accumulator group, comparing the internal pressure with a preset pressure level, and respectively controlling the on-off of reversing valves and electromagnetic valves according to a comparison result. The present invention has the beneficial effects that all hydraulic loads can be automatically loaded or automatically unloaded, so that the wave energy device operates in a full load state or in an optimal energy conversion efficiency state.

A hydraulic system includes an engine; at least one hydraulic pump operatively coupled to the engine for transfer of mechanical power therebetween; and a controller operatively coupled to the engine and the at least one hydraulic pump. The controller is configured to determine a lug speed error as a difference between a target lug speed value and a speed of the engine, set at least one closed-loop gain to zero when the speed of the engine is greater than or equal to the target lug speed value, set the at least one closed-loop gain to a non-zero value when the speed of the engine is less than the target lug speed value, generate a pump control signal by scaling the lug speed error by the at least one closed-loop gain.

The present disclosure relates to a backhoe loader energy recovery and reuse system and a control method thereof, and a backhoe loader, wherein the system comprises: an actuator, configured to drive a working device to perform an action with hydraulic oil as a medium, and having a first cavity and a second cavity; a reversing valve, having a first working oil port communicated with the first cavity and a second working oil port communicated with the second cavity, the reversing valve being configured to reverse the actuator; a stabilizing valve group, having a first oil port, a second oil port, a third oil port and a fourth oil port, the first oil port and the second oil port being communicated with the first cavity and the second cavity, respectively, and the third oil port being communicated with an oil tank; and an energy storage part, communicated with the fourth oil port and configured to store hydraulic energy; wherein the first oil port and the third oil port have a first communication state therebetween, in which the hydraulic oil in the first cavity can enter the oil tank; the second oil port and the fourth oil port can be selectively connected or disconnected, and in a connected state, the second cavity is communicated with the energy storage part.

A control system may be used to control actuators that actuate movement of flight control surfaces of an aircraft. Each actuator is couplable to a flight control surface and includes a motion control assembly having a hydraulic motor and a drive path from the hydraulic motor to the flight control surface. Each hydraulic motor includes an extend port and a retract port. The system includes a hydraulic control module fluidly connected to the extend port and the retract port of each hydraulic motor and a controller operable to output hydraulic power from the hydraulic control module to the motion control assembly to actuate movement of the flight control surfaces. The controller is configured to identify an actuator that positionally leads the other actuators and reduce hydraulic power to the motion control assembly assigned to such actuator.

A movement apparatus for industrial automation, in particular for handling a workpiece, including: a fluidic actuator to which a pressurised fluid can be applied, with a actuator element, and a pressurised fluid provision device which is designed to apply the pressurised fluid to the fluidic actuator according to a control signal, in order to move the actuator element into a predefined position. The pressurised fluid provision device is designed to, whilst the actuator element is in movement to the predefined position, successively change a pressure of the pressurised fluid and/or a throttle opening which is used for providing the pressurised fluid, according to a predefined value course, in order to adapt the movement of the actuator element.

A hydraulic drive unit for a shaping machine comprising a pump driven by a motor, a closed-loop or open-loop control unit for closed-loop and/or open-loop control of the drive unit to a reference operating point of the drive unit, and a memory connected to the closed-loop or open-loop control unit, wherein a relationship between a parameter characteristic of a sound directly or indirectly caused by the drive unit and a data set representing various operating points of the drive unit is stored in the memory and the closed-loop or open-loop control unit is adapted to select the reference operating point on the basis of the relationship.

A method for the open-loop control of a pump system (5) includes accessing a hydraulic calculation model by an electronic control unit, which includes, for various operating states of a transmission, information regarding oil supplies of two pumps (P, S) of the pump system (5) and information regarding oil demands of the transmission. The method also include ascertaining a certain oil supply ({dot over (V)}.sub.supply), which the two pumps (P, S) provide in a certain operating state of the transmission according to the hydraulic calculation model. In addition, the method includes ascertaining a certain oil demand ({dot over (V)}.sub.demand), which the hydraulic system (1) requests of the two pumps (P, S) in the certain operating state of the transmission according to the hydraulic calculation model.

A working machine including a hydraulic system. The hydraulic system includes: a hydraulically actuated device; a hydraulic pump assembly for supplying a variable output of hydraulic fluid to the hydraulically actuated device; an electric motor coupled to the hydraulic pump assembly such that output of hydraulic fluid from the hydraulic pump assembly is varied by adjusting the rotation speed of the electric motor; and a motor controller configured to: generate a motor control signal for operating the electric motor based on a motor speed command signal. The hydraulic system does not include a rotor positioning sensor arranged to sense the rotational position of a rotor of the electric motor.