Abstract: A direct drive servovalve device includes (i) a servovalve motor having a stator and a rotor assembly configured to rotate relative to the stator, (ii) a valve member coupled to the rotor assembly, and (iii) a sensor assembly. The sensor assembly includes an interface configured to couple to a controller that controls the servovalve motor, a set of programmable Hall sensors coupled to the interface, and a support. The support (e.g., a ring-shaped collar or sleeve) supports the set of Hall sensors at an installation location which is (i) adjacent to the rotor assembly and (ii) fixed relative to the stator. The set of programmable Hall sensors is configured to provide a set of position signals to the controller through the interface. The set of position signals identifies a rotational position of the rotor assembly relative to the stator.

Abstract: A direct drive servovalve device includes (i) a servovalve motor having a stator and a rotor assembly configured to rotate relative to the stator, (ii) a valve member coupled to the rotor assembly, and (iii) a sensor assembly. The sensor assembly includes an interface configured to couple to a controller that controls the servovalve motor, a set of programmable Hall sensors coupled to the interface, and a support. The support (e.g., a ring-shaped collar or sleeve) supports the set of Hall sensors at an installation location which is (i) adjacent to the rotor assembly and (ii) fixed relative to the stator. The set of programmable Hall sensors is configured to provide a set of position signals to the controller through the interface. The set of position signals identifies a rotational position of the rotor assembly relative to the stator.

Abstract: An electrical command signal to a direct drive valve is compensated by a digital signal processor to cause the output hydraulic fluid flow from the valve to conform to a desired predetermined flow. The compensation is accomplished by measuring flow from the valve using a standard direct drive valve code. This flow is compared to a desired flow and the difference is taken on a point to point basis. A compensation is then calculated to change the command signal so as to cause the flow to be according to the desired flow.