A servo valve for precisely controlling a position of a pneumatic cylinder does not require a servo amplifier and a small sized and/or high durability servo valve unit. The servo valve comprises a unit body having first and second portions, first and second valve portions, first and second seal members that open and close the first and second valve portions, respectively, first and second drive mechanisms that drive first and second seal members by first and second electric pulses, respectively, a supply flow path between the first end and first valve, an exhaust flow path between the second end and second valve, a common flow path connected to the supply and exhaust flow paths via first and second valve portions, and a drive flow path connected to the pneumatic actuator. First and second drive mechanisms are arranged in a drive mechanism arrangement portion located between first and second end portions.

A servo valve for precisely controlling a position of a pneumatic cylinder does not require a servo amplifier and a small sized and/or high durability servo valve unit. The servo valve comprises a unit body having first and second portions, first and second valve portions, first and second seal members that open and close the first and second valve portions, respectively, first and second drive mechanisms that drive first and second seal members by first and second electric pulses, respectively, a supply flow path between the first end and first valve, an exhaust flow path between the second end and second valve, a common flow path connected to the supply and exhaust flow paths via first and second valve portions, and a drive flow path connected to the pneumatic actuator. First and second drive mechanisms are arranged in a drive mechanism arrangement portion located between first and second end portions.

Disclosed herein are embodiments of a servo-control system comprising at least one pneumatic actuator comprising a movable member, at least one proportional pneumatic valve configured to control fluid flow between the at least one pneumatic actuator and a pressurized fluid supply or a vent, a plurality of pressure sensors each configured to independently measure pressure in a respective supply line to the at least one pneumatic actuator, at least one position sensor configured to measure a position of the moveable member, and a controller. The controller is configured to determine a control signal based at least in part on pressure measurements of the plurality of pressure sensors and a position measurement of the at least one position sensor, and apply the control signal to at least one proportional pneumatic valve to move the movable member to a target position.

Disclosed herein are embodiments of a servo-control system comprising at least one pneumatic actuator comprising a movable member, at least one proportional pneumatic valve configured to control fluid flow between the at least one pneumatic actuator and a pressurized fluid supply or a vent, a plurality of pressure sensors each configured to independently measure pressure in a respective supply line to the at least one pneumatic actuator, at least one position sensor configured to measure a position of the moveable member, and a controller. The controller is configured to determine a control signal based at least in part on pressure measurements of the plurality of pressure sensors and a position measurement of the at least one position sensor, and apply the control signal to at least one proportional pneumatic valve to move the movable member to a target position.

A hydrostatic actuator system includes an electric motor for delivering a hydraulic fluid via a piston unit. The actuator system is operating using a method in which a change in volume caused by a temperature change is sensed by a pressure measurement. The method reliably identifies a state of the transfer of the hydraulic fluid from a planetary roller transmission compartment into the master piston. The pressure measurement is continuously evaluated, and, in the event of a negative signal of the pressure measurement, suction of the hydraulic fluid by a planetary roller transmission lying in the hydraulic fluid between the electric motor and the piston unit into the piston unit is recognized and a fault signal is output.

A hydrostatic actuator system includes an electric motor for delivering a hydraulic fluid via a piston unit. The actuator system is operating using a method in which a change in volume caused by a temperature change is sensed by a pressure measurement. The method reliably identifies a state of the transfer of the hydraulic fluid from a planetary roller transmission compartment into the master piston. The pressure measurement is continuously evaluated, and, in the event of a negative signal of the pressure measurement, suction of the hydraulic fluid by a planetary roller transmission lying in the hydraulic fluid between the electric motor and the piston unit into the piston unit is recognized and a fault signal is output.

A system and method is provided for monitoring a hydraulic power system having at least one light emitter and a button. The method includes powering on the hydraulic power system, receiving an actuation at the button and detecting a release of the button after a first time interval, and entering a diagnostic state. The method further includes retrieving a code and displaying the code by turning on the emitter in a first pattern. In some embodiments, a system and method is provided for regulating a temperature of a hydraulic power system. In some embodiments, a system and method is provided for controlling operation of a hydraulic torque wrench.

A system and method is provided for monitoring a hydraulic power system having at least one light emitter and a button. The method includes powering on the hydraulic power system, receiving an actuation at the button and detecting a release of the button after a first time interval, and entering a diagnostic state. The method further includes retrieving a code and displaying the code by turning on the emitter in a first pattern. In some embodiments, a system and method is provided for regulating a temperature of a hydraulic power system. In some embodiments, a system and method is provided for controlling operation of a hydraulic torque wrench.

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.