The invention relates to a method for generating a control variable trajectory for an actuator so as to influence an input variable of a system, wherein a set point is supplied to the output variable of the system of a trajectory planning procedure, which from the set point generates a trajectory of constrained input values for a filter integrator chain and a trajectory of flat desired states, wherein the trajectory of constrained input values and the trajectory of flat desired states are supplied to a flatness-based feedforward control procedure that generates therefrom the control variable trajectory for the actuator, wherein in the trajectory planning procedure so as to generate the trajectory of constrained input values at least one constraint is applied in dependence upon the trajectory of flat desired states.

A movable-blade operation system for a hydraulic machine according to an embodiment includes an oil hydraulic cylinder installed within a rotational shaft, a bidirectional pump, a pump drive motor, a control unit, and an oil head installed in the hydraulic machine. The bidirectional pump selectively feeds pressurized hydraulic oil to one of a first cylinder chamber and a second cylinder chamber. The oil head couples the rotational shaft rotatably, and the hydraulic oil fed from the bidirectional pump to the first cylinder chamber and the second cylinder chamber flows through the oil head. The bidirectional pump, the pump drive motor, and the control unit are installed outside the hydraulic machine.

A hydraulically-actuated device comprises a self-contained fluid reservoir comprising a tank for receiving a fluid, a reservoir port, and a flexible diaphragm. An actuation member comprises a hydraulically actuated piston in a cylinder. A pump case comprises an inlet port and an outlet port, the inlet port in fluid communication with the reservoir port, and the outlet port in fluid communication with the actuation member. A pump is within the pump case. The pump can be a reversible pump. The flexible diaphragm can flex in to the fluid reservoir when the pump transfers a fluid from the fluid reservoir to the actuation member and can flex away from the fluid reservoir when the pump transfers fluid from the actuation member to the fluid reservoir. The flexible diaphragm can hermetically seal a fluid within the fluid reservoir and have a second side in communication with atmospheric pressure.

A hydraulic valve assembly includes an algorithm stored in an internal memory of the hydraulic valve assembly that determines a spool correction command based on a flow demand which is calculated for obtaining a target single port pressure or a target delta pressure using one or more port pressure measurements. The spool correction command is sent to an upper level controller of the hydraulic valve assembly, and the upper level controller uses the spool correction command to obtain an optimal displacement of a spool inside the valve assembly.

When a swing motor and a boom cylinder are driven simultaneously, a hydraulic drive system appropriately adjusts a distribution of torques between hydraulic pumps and feeds back a torque actually consumed by the hydraulic pump for actuating the swing motor accurately to the hydraulic pump for actuating the boom cylinder. To that end, when boom raising and swinging are performed simultaneously, the hydraulic drive system corrects an allowable torque of a hydraulic pump 302 that supplies a hydraulic fluid to a swing motor 3c so as to be lowered by a certain ratio, reducing allowable torques of hydraulic pumps 102 and 202 that supply a hydraulic fluid to a boom cylinder 3a by torques consumed by the hydraulic pumps 102 and 202 that supply a hydraulic fluid to the swing motor 3c.

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 harvester head having at least one hydraulic actuator with a cylinder and a piston. The hydraulic actuator having at least a cylinder chamber and a piston rod chamber, both chambers being connected to a hydraulic circuit. The piston separating the cylinder chamber and the piston rod chamber, a cavity provided in the piston, hydraulically connecting the cylinder chamber with the piston rod chamber and a check valve in connection with the cavity that allows hydraulic medium flow in an opening direction of the check valve.

A landing gear system for an aircraft includes a retractable landing gear assembly, a hydraulic actuator for actuating movement part, for example a bogie of the landing gear assembly, and an accumulator associated with the actuator. The accumulator comprises a volume of pressurised gas separated from hydraulic fluid by a separator piston. Travel of the separator piston beyond a certain position is indicative of a fault. The accumulator includes a snubbing device that acts to slow movement of the separator piston beyond that position. A monitoring system measures the time taken for the movement of the landing gear part effected by the hydraulic actuator. If the measured time is longer than a threshold time, that is indicative of a possible fault in the accumulator, that might, without the snubbing, remain undetected and/or hidden from view.

The invention relates to a vehicle seat for a vehicle, comprising a seat part that has a seat part frame, comprising a backrest part and comprising a first and a second switching console element which each comprise at least one control element for actuating at least one function of an actuator element of the vehicle, the first switching console element being arranged on a first side of the seat part and the second switching console element being arranged on a second side of the seat part so as to extend in the longitudinal direction of the vehicle seat, the seat part and/or the backrest part being designed so as to be adjustable with respect to a degree of inclination, it being possible to change a relative position of a first portion of the first switching console element, with respect to the vehicle seat, it being possible to transfer the change in the relative position of the first portion of the first switching console element into a change in a relative position of a first portion of the second switching console element, with respect to the vehicle seat, by means of a transmission system which is free of electronic components.

One object is to calculate the position of a rod of a linear actuator with a high precision. The linear actuator includes a rod capable of moving in an axial direction relative to a housing. The rod is moved by rotation of an output shaft of a motor. A position sensor for sensing the relative position of the rod relative to a preset reference position is provided in the housing. A rotation sensor for sensing the rotation angle of the output shaft of the motor is provided in the vicinity of the motor. The linear actuator includes a position calculating unit for calculating the position of the rod based on a position sensing value of the position sensor and a rotation angle sensing value of the rotation sensor.