A servo regulator includes a servo piston coupled with a swash plate, a pressure chamber provided to face an end portion of the servo piston, a spool configured to control a pressure in the pressure chamber by being moved by a solenoid, a biasing member configured to bias the spool against a thrust of the solenoid, and a feedback portion configured to change a biasing force of the biasing member in accordance with tilting of the swash plate, wherein the feedback portion is coupled with the swash plate via the servo piston.

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.

A triplex pneumatic architecture system is disclosed having first, second, and third pneumatic subsystems where triplex redundancy may be accomplished by measuring only one particular node in each system, such as a measured current of the servo valve. Each of the first, second, and third pneumatic subsystems are configured to control a separate redundant pneumatic actuation assembly. Each subsystem may comprise a current sensor to measure a control current from a servo driver to a servo valve that controls the pneumatic actuation assembly to output a measured current value, and a dump valve coupled to a relay. Each processor is configured to generate a termination signal to actuate the first relay to open the first dump valve. The triplex pneumatic architecture system further includes a communication bus to communicatively couple each of the first, second, and third pneumatic subsystems. Each processor is configured to generate the termination signal and to communicate the termination signal to one or more of the relays when one measured current value deviates from the two other measured current values by a predetermined error value.

A triplex pneumatic architecture system is disclosed having first, second, and third pneumatic subsystems where triplex redundancy may be accomplished by measuring only one particular node in each system, such as a measured current of the servo valve. Each of the first, second, and third pneumatic subsystems are configured to control a separate redundant pneumatic actuation assembly. Each subsystem may comprise a current sensor to measure a control current from a servo driver to a servo valve that controls the pneumatic actuation assembly to output a measured current value, and a dump valve coupled to a relay. Each processor is configured to generate a termination signal to actuate the first relay to open the first dump valve. The triplex pneumatic architecture system further includes a communication bus to communicatively couple each of the first, second, and third pneumatic subsystems. Each processor is configured to generate the termination signal and to communicate the termination signal to one or more of the relays when one measured current value deviates from the two other measured current values by a predetermined error value.

A valve body for a servovalve is provided, the valve body comprising: a first surface; a second surface offset from the first surface; a first passage extending through the body between the first and second surfaces from a first side of the body to a second side thereof; a second passage extending from the first surface towards the second surface and intersecting the first passage; a supply port joined with the first passage; a control port joined with the first passage; a return port joined with the first passage, wherein the return port comprises a third passage extending through the body between the first and second surfaces from a third side of the body to a fourth side thereof and intersecting with the first passage.

A valve body for a servovalve is provided, the valve body comprising: a first surface; a second surface offset from the first surface; a first passage extending through the body between the first and second surfaces from a first side of the body to a second side thereof; a second passage extending from the first surface towards the second surface and intersecting the first passage; a supply port joined with the first passage; a control port joined with the first passage; a return port joined with the first passage, wherein the return port comprises a third passage extending through the body between the first and second surfaces from a third side of the body to a fourth side thereof and intersecting with the first passage.

A hydraulic system is disclosed. The hydraulic system may include a source of pressurized fluid; a tank; a hydraulic actuator including a first chamber and a second chamber; a first independent metering valve disposed between and fluidly connected to the source, the tank, and the first chamber of the hydraulic actuator; and a second independent metering valve disposed between and fluidly connected to the source, the tank, and the second chamber of the hydraulic actuator. Each of the first independent metering valve and the second independent metering valve may include a spool and a valve actuator disposed on one side of the spool. The valve actuator may include a push coil, a pull coil, and a force feedback mechanism configured to balance a force of the push coil and the pull coil.

An example valve includes: a first port; a second port; a third port; a poppet configured to be subjected to (i) a first fluid force by fluid of the first port acting on the poppet in a proximal direction toward a poppet seat, and (ii) a second fluid force by fluid of the second port acting on the poppet in a distal direction; a pilot piston configured to be subjected to a pilot fluid force by a pilot fluid signal received at the third port; a check spring applying a spring force on the poppet in the proximal direction; and pilot spring applying a pilot spring force on the pilot piston in the proximal direction.

An electrohydraulic servo valve (EHSV) includes a housing assembly, a spool valve, an armature, a control mechanism, and a feedback spring. The spool valve is movably disposed within the housing assembly. The armature is rotationally mounted on the housing assembly. The control mechanism is coupled to the armature and is rotatable therewith. The feedback spring is coupled between the control mechanism and the spool valve, and includes a helical coil that is disposed on and engages the control mechanism, and a cantilever portion that extends from the helical portion to a terminus that engages the spool valve.