A control device controls movement of a valve body of a valve device and estimates a flow rate of the valve device; determines, on the basis of an input target flow rate value and the flow rate estimate, whether or not the flow of an operating fluid in the valve device is in a transient flow state; calculates an opening command on the basis of the target flow rate value and an upstream-downstream pressure difference of the valve device; and controls the movement of the valve body. When the control device determines that the flow is not in the transient flow state, it controls the movement of the valve body on the basis of the opening command, and when the control determines that the flow is in the transient flow state, it controls the movement of the valve body on the basis of the target flow rate value.

A positioner according to the present invention includes: an electro-pneumatic converter that converts an input electric signal into a pneumatic signal and controls the valve opening of a regulating valve by driving an operational unit in accordance with the pneumatic signal; an operating-point searching unit that changes the electric signal by performing open loop control to search for an operating point indicating a target valve-opening value of the regulating valve when an output air pressure of the pneumatic signal starts to change; and a PST executing unit that executes a PST on the regulating valve by using the operating point found by the operating-point searching unit. The operating-point searching unit sets the operating point based on a value of the electric signal when the output air pressure matches a first reference value.

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.

To achieve reduction of fuel consumption and enhancement of operability, in a hydraulic control circuit provided with a bypass oil passage formed by being branched from a discharge line of a hydraulic pump and extending to an oil tank, and a bypass valve having variable opening area for controlling a flow rate of the bypass oil passage, and to accurately perform pump pressure control through opening area control of the bypass valve without being affected by a condition of each time. The hydraulic control circuit is configured to perform closed-loop control of the opening area of the bypass valve so that the pump pressure is maintained at a set pressure, during nonoperation of the operation lever; on the other hand, to perform open-loop control for reducing the opening area of the bypass valve depending on the operation input of the operation lever, during an operation of the operation lever, and further configured to correct on the basis of the opening area of the bypass valve during the closed-loop control, the correspondence relationship between the operation input of the operation lever and the opening area of the bypass valve during the open-loop control.

To achieve reduction of fuel consumption and enhancement of operability, in a hydraulic control circuit provided with a bypass oil passage formed by being branched from a discharge line of a hydraulic pump and extending to an oil tank, and a bypass valve having variable opening area for controlling a flow rate of the bypass oil passage, and to accurately perform pump pressure control through opening area control of the bypass valve without being affected by a condition of each time. The hydraulic control circuit is configured to perform closed-loop control of the opening area of the bypass valve so that the pump pressure is maintained at a set pressure, during nonoperation of the operation lever; on the other hand, to perform open-loop control for reducing the opening area of the bypass valve depending on the operation input of the operation lever, during an operation of the operation lever, and further configured to correct on the basis of the opening area of the bypass valve during the closed-loop control, the correspondence relationship between the operation input of the operation lever and the opening area of the bypass valve during the open-loop control.

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 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.

A positioner according to the present invention includes: an electro-pneumatic converter that converts an input electric signal into a pneumatic signal and controls the valve opening of a regulating valve by driving an operational unit in accordance with the pneumatic signal; an operating-point searching unit that changes the electric signal by performing open loop control to search for an operating point indicating a target valve-opening value of the regulating valve when an output air pressure of the pneumatic signal starts to change; and a PST executing unit that executes a PST on the regulating valve by using the operating point found by the operating-point searching unit. The operating-point searching unit sets the operating point based on a value of the electric signal when the output air pressure matches a first reference value.

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 control device controls movement of a valve body of a valve device and estimates a flow rate of the valve device; determines, on the basis of an input target flow rate value and the flow rate estimate, whether or not the flow of an operating fluid in the valve device is in a transient flow state; calculates an opening command on the basis of the target flow rate value and an upstream-downstream pressure difference of the valve device; and controls the movement of the valve body. When the control device determines that the flow is not in the transient flow state, it controls the movement of the valve body on the basis of the opening command, and when the control determines that the flow is in the transient flow state, it controls the movement of the valve body on the basis of the target flow rate value.