A hydraulic servo control system, comprising:
- a servo actuator having a housing with an actuator chamber, a first actuator port a second actuator port, and an actuator piston positioned within the actuator chamber, and a piston rod attached to the actuator piston, the actuator piston being adapted to bi-directionally slide in a linear direction within the actuator chamber, the actuator piston being positioned within the actuator chamber separating the actuator chamber to thereby define a first actuator chamber and a second actuator chamber, the first actuator port in fluid communication with the first actuator chamber and the second actuator port in fluid communication with the second actuator chamber;
- and
- a servovalve connected to the servo actuator, the servovalve comprising;
- a servovalve body having a first control port adapted to receive a first control signal, a second control port adapted to receive a second control signal, an inlet port adapted to receive a high pressure fluid, a first outlet port in fluid communication with the first actuator port, a second outlet port in fluid communication with the second actuator port, and a longitudinal bore formed within the servovalve body, the longitudinal bore including a first bore end and a second bore end, wherein the first control signal is adapted to apply a force at the first bore end and the second control signal is adapted to apply a force at the second bore end;
- and
- a spool positioned in the longitudinal bore and being adapted for linear bi-directional motion within the longitudinal bore between the first bore end and the second bore end in response to alternating opposing forces being applied at the first and second bore ends, the spool comprising
- a first end land;
- a second end land;
- and
- an intermediate land having a first side, a second side opposite the first side, the intermediate land being positioned between the first end land and the second end land in a spaced-apart, axially aligned relationship such that a first annular space is defined between the first end land and the first side of the intermediate land and a second annular space is defined between the second end land and the second side of the intermediate land, the intermediate land further having at least one fluid passageway formed in and extending through the intermediate land from the first side to the second side to establish fluid communication between the first annular space and the second annular space to provide a fluid pressure feedback between the first and second annular spaces and a jet provided within the at least one fluid passageway to provide a fluid restriction between the first and second annular spaces,
- wherein the inlet port is in alternating fluid communication with the first and the second annular spaces dependent on the position of the spool with respect to its linear bi-directional motion, and the first and second outlet ports are further in fluid communication with the first and second annular spaces to alternatingly provide the high pressure fluid to the first and second actuator chambers via the first and second actuator ports of the servo actuator.