US 5,806,805 AGranted

Fault tolerant actuation system for flight control actuators

AssigneeThe Boeing Company

InventorsRalph P. Elbert, Michael A. Hafner

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Abstract

A fault tolerant actuation system (12) for flight control systems is provided. The fault tolerant actuation system (12) includes a plurality of primary flight computers (14a, 14b, and 14c) with corresponding power control units (24a, 24b, and 24c). Each power control unit includes a remote electronic unit (18a, 18b, and 18c), an electro-hydraulic servo valve (26a, 26b, and 26c), and an actuator (28a, 28b, and 28c). The actuators are linked to a flight control surface (30) to control its position. The electro-hydraulic servo valves (26a, 26b, and 26c) and the actuators (28a, 28b, and 28c) include sensors that monitor their operation. Each RE (18a, 18b, and 18c) generates a control current (i.sub.1, i.sub.2, and i.sub.3) based upon commands of the corresponding primary flight computer as well as feedback data transmitted from the sensors of the corresponding electro-hydraulic servo valve and actuator only. The feedback data is transmitted along separate servo loops having separate compensations (66a, 70a). A current equalization control (34a, 34b, and 34c) equalizes the control currents with one another. A force fight equalization control (36a, 36b, and 36c) equalizes the forces of the actuators with one another.

Claims22

Dependent claims

A fault tolerant actuation system for a flight control system comprising:

a plurality of primary flight computers, each of said plurality of primary flight computers generating an actuator command to direct the position of a flight control surface;
a plurality of power control units, each of said plurality of power control units coupled to a corresponding primary flight computer of said plurality of primary flight computers for receiving the actuator commands of the corresponding primary flight computer and controlling the flight control surface, each of said plurality of power control units including:
an actuator having a ram for moving the flight control surface;
an electro-hydraulic servo valve having a plurality of control coils and an armature for directing the position of a spool that controls the position of the ram of said actuator;
a plurality of sensors for producing feedback signals indicative of the operation of said actuator and said electro-hydraulic servo valve;
a remote electronic unit (RE) for processing the actuator commands and the feedback signals to generate a control current, said RE applying the control current to a predetermined one of said plurality of control coils of all of said electro-hydraulic servo valves of the fault tolerant actuation system thereby contributing to the net magnetic flux capable of imparting a torque on the armature of said electro-hydraulic servo valve to direct the position of the spool;
a trim coil amplifier for inputting a trim current to said electro-hydraulic servo valve;
and
a plurality of servo loops for forwarding the feedback signals from said plurality of sensors to said RE.

6 more elements

Dependencies are inferred from the claim text.