Patent ID: 8583293

Claim:
A flight control surface actuation system, comprising: a plurality of differential pressure (DP) sensors, each DP sensor configured to sense a differential fluid pressure across a hydraulically-operated actuator and supply a differential pressure signal representative of the sensed differential fluid pressure; a plurality of user interface sensors, each user interface sensor configured to sense movement of a user interface and supply a position command signal representative of the sensed movement; a position sensor configured to sense flight control surface position and supply a flight control surface position signal representative of the sensed flight control surface position; a flight control module coupled to receive the differential pressure signals, the position command signals, and the flight control surface position signal, the flight control module configured to process these signals and generate a plurality of force fight command signals; and a plurality of actuator controls, each actuator control coupled to receive one of the force fight command signals and one of the position command signals and configured, in response to these signals, to supply a plurality of substantially equal actuator commands, wherein the flight control module comprises a force fight mitigation function that comprises: a DP averaging function coupled to receive the differential pressure signals and configured, upon receipt thereof, to supply a value representative of an average of the sensed differential fluid pressures; a plurality of subtraction functions, each subtraction function coupled to receive one of the differential fluid pressure signals and the value representative of the average of the sensed differential fluid pressures and configured, upon receipt thereof, to supply a plurality of differential fluid pressure offsets; a plurality of proportional-plus-integral (PI) control paths, each PI control path coupled to receive one of the differential fluid pressure offsets and configured, upon receipt thereof, to supply a differential pressure equalization output signal; a position command averaging function coupled to receive the position command signals and configured, upon receipt thereof, to supply a value representative of an average of the position command signals; a plurality of gains, each gain coupled to receive the flight control surface position signal and configured, upon receipt thereof, to supply an actuator surface position equalization command signal; and mathematical logic coupled to receive the differential pressure equalization output signals, the value representative of the average of the position command signals, and the actuator surface position equalization command signals and configured, upon receipt thereof, to supply the plurality of force fight command signals.