US 4,418,610 AGranted

Electrohydraulic control system

AssigneeThe United States of America as represented by the Secretary of the Navy

InventorJohn W. Holtrop

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Abstract

An electrohydraulic control system with mechanical position sensing feedb is presented. A movable flight control canard is rotatably operated for providing flight control of the missile. A hydraulically powered actuator is mounted to the airframe with the canard being secured to the actuator shaft for controlled rotation of the canard. Hydraulic fluid under pressure enters the actuator at its base controlled via a rotary valve. A stepper motor is mounted to the canard and is geared to drive the rotary valve as determined by digital control signals generated by the missile guidance computer. When the stepper motor receives a train of pulses, the stepper motor rotor rotatingly moves the rotary valve from the null or closed position to an open position admitting hydraulic fluid into the rotary actuator causing the canard to turn. The stepper motor rotates along with the canard and provides position feedback for closing the rotary valve when the canard has reached the equilibrium position determined by the control signal.

Claims4

Dependent claims

A hydraulic system for positioning a movable member which is mounted for rotation about an axis, said hydraulic system comprising:

actuator means for positioning said movable member, said actuator means being connected to said movable member and responsive in rotation about said axis to hydraulic fluid under pressure;
valve means operatively connected to said actuator means for controlling said hydraulic fluid, said valve means being actuatable between a first state preventing transmission of hydraulic fluid pressure to said actuator means and conduction of hydraulic fluid from said actuator means and at least one additional state permitting transmission of hydraulic fluid pressure to said actuator means and conduction of hydraulic fluid from said actuator means, said valve means being configured for movement about said axis;
and
servo control means responsive to a control signal and operatively connected to said valve means for controlling said valve means between said first state and said additional state, said servo control means being attached to said movable member and movable about said axis.

1 more element

Dependencies are inferred from the claim text.