A pump control assembly for controlling a variable displacement hydraulic pump includes a spool mounted within a valve block. The spool is configured to move between a first and a second position within the valve block so as to selectively control the displacement of the attached pump. The pump control assembly further includes first and second chambers that each apply a force to opposite ends of the spool. The first chamber is positioned at a first end of the spool in fluid communication with a pump output port. The second chamber is positioned at a second end of the spool and in fluid communication with a hydraulic tank port and a proportional pressure reducing valve. The second chamber also includes a piston and first and second springs positioned on either side of the piston. The proportional pressure reducing valve provides a regulated pressure to a first side of the piston along with the first spring, and the hydraulic tank port provides a tank pressure on the opposite side of the piston along with the second spring. The pump control assembly also includes a stop structure having a positive stop that limits movement of the piston in a direction toward the first chamber.

A pump control assembly for controlling a variable displacement hydraulic pump includes a spool mounted within a valve block. The spool is configured to move between a first and a second position within the valve block so as to selectively control the displacement of the attached pump. The pump control assembly further includes first and second chambers that each apply a force to opposite ends of the spool. The first chamber is positioned at a first end of the spool in fluid communication with a pump output port. The second chamber is positioned at a second end of the spool and in fluid communication with a hydraulic tank port and a proportional pressure reducing valve. The second chamber also includes a piston and first and second springs positioned on either side of the piston. The proportional pressure reducing valve provides a regulated pressure to a first side of the piston along with the first spring, and the hydraulic tank port provides a tank pressure on the opposite side of the piston along with the second spring. The pump control assembly also includes a stop structure having a positive stop that limits movement of the piston in a direction toward the first chamber.

The subject matter of this specification can be embodied in, among other things, an electrohydraulic positioning control system that includes a shuttle valve configured to direct fluid flow between a selectable one of a first fluid port and a second fluid port, and a fluid outlet configured to be fluidically connected to a fluid actuator, a first servo valve controllable to selectably permit and block flow between the first fluid port, a fluid source, and a fluid drain, a second servo valve controllable to selectably permit and block flow between the second fluid port, the fluid source, and the fluid drain, a first servo controller configured to provide a first health signal and control the first servo valve based on a second health signal, and a second servo controller configured to provide the second health signal and control the second servo valve based on the first health signal.

The subject matter of this specification can be embodied in, among other things, an electrohydraulic positioning control system that includes a shuttle valve configured to direct fluid flow between a selectable one of a first fluid port and a second fluid port, and a fluid outlet configured to be fluidically connected to a fluid actuator, a first servo valve controllable to selectably permit and block flow between the first fluid port, a fluid source, and a fluid drain, a second servo valve controllable to selectably permit and block flow between the second fluid port, the fluid source, and the fluid drain, a first servo controller configured to provide a first health signal and control the first servo valve based on a second health signal, and a second servo controller configured to provide the second health signal and control the second servo valve based on the first health signal.

Provided is a double nozzle type positioner, which includes a flapper (1), a first nozzle (2) and a second nozzle (3) disposed at both sides based on the flapper (1), a first orifice (4) configured to maintain a constant pressure of the first nozzle (2), a second orifice (5) configured to maintain a constant pressure of the second nozzle (3), a first pilot valve (6) having an input portion connected to a feed pressure, a second pilot valve (7) having an input portion connected to an output portion of the first pilot valve (6), a discharge hole (8) connected to an output portion of the second pilot valve (7), and an actuator (9) connected to the output portion of the first pilot valve (6) and the input portion of the second pilot valve (7). If the first nozzle (2) is opened due to the movement of the flapper (1), the second nozzle (3) is closed, and if the first nozzle (2) is closed, the second nozzle (3) is opened.

Provided is a double nozzle type positioner, which includes a flapper (1), a first nozzle (2) and a second nozzle (3) disposed at both sides based on the flapper (1), a first orifice (4) configured to maintain a constant pressure of the first nozzle (2), a second orifice (5) configured to maintain a constant pressure of the second nozzle (3), a first pilot valve (6) having an input portion connected to a feed pressure, a second pilot valve (7) having an input portion connected to an output portion of the first pilot valve (6), a discharge hole (8) connected to an output portion of the second pilot valve (7), and an actuator (9) connected to the output portion of the first pilot valve (6) and the input portion of the second pilot valve (7). If the first nozzle (2) is opened due to the movement of the flapper (1), the second nozzle (3) is closed, and if the first nozzle (2) is closed, the second nozzle (3) is opened.

A hydraulic system includes at least one hydraulic unit (2) having at least one flow path (14, 16, 18), an hydraulic actuator (22), provided for influencing a hydraulic flow through the flow path (14, 16, 18), at least one sensor device (24, 26), and a control device (10) for controlling the hydraulic actuator (22). The at least one sensor device (24, 26) includes a storage device (32) provided for containing information specifying the hydraulic unit (2). The control device (10) is configured to receive the information stored in the storage device (32) of the sensor device (24, 26) and to set up a control of the hydraulic actuator (22) based on the received information specifying the hydraulic unit (2). A method is provided for controlling the hydraulic actuator.

A hydraulic system includes at least one hydraulic unit (2) having at least one flow path (14, 16, 18), an hydraulic actuator (22), provided for influencing a hydraulic flow through the flow path (14, 16, 18), at least one sensor device (24, 26), and a control device (10) for controlling the hydraulic actuator (22). The at least one sensor device (24, 26) includes a storage device (32) provided for containing information specifying the hydraulic unit (2). The control device (10) is configured to receive the information stored in the storage device (32) of the sensor device (24, 26) and to set up a control of the hydraulic actuator (22) based on the received information specifying the hydraulic unit (2). A method is provided for controlling the hydraulic actuator.

A hydraulic system includes at least one hydraulic unit (2) having at least one flow path (14, 16, 18), an hydraulic actuator (22), provided for influencing a hydraulic flow through the flow path (14, 16, 18), at least one sensor device (24, 26), and a control device (10) for controlling the hydraulic actuator (22). The at least one sensor device (24, 26) includes a storage device (32) provided for containing information specifying the hydraulic unit (2). The control device (10) is configured to receive the information stored in the storage device (32) of the sensor device (24, 26) and to set up a control of the hydraulic actuator (22) based on the received information specifying the hydraulic unit (2). A method is provided for controlling the hydraulic actuator.

A hydraulic system includes at least one hydraulic unit (2) having at least one flow path (14, 16, 18), an hydraulic actuator (22), provided for influencing a hydraulic flow through the flow path (14, 16, 18), at least one sensor device (24, 26), and a control device (10) for controlling the hydraulic actuator (22). The at least one sensor device (24, 26) includes a storage device (32) provided for containing information specifying the hydraulic unit (2). The control device (10) is configured to receive the information stored in the storage device (32) of the sensor device (24, 26) and to set up a control of the hydraulic actuator (22) based on the received information specifying the hydraulic unit (2). A method is provided for controlling the hydraulic actuator.