Multi-axis force stick, self-trimmed aircraft flight control system

Claim 1

A control system for providing principal manual control to an aircraft having four control axes, said four control axes including pitch, roll, yaw and lift/speed, said control system including: a plurality of positionable aerodynamic surfaces, the positions of which control the aircraft in said four control axes; control means operable by a pilot to provide desired position command signals indicative of desired aerodynamic surface positions; and positioning means connected between said control means and said aerodynamic surfaces and operative in response to said desired position command signals applied thereto to control the positioning of said aerodynamic surfaces; characterized by said control means comprising: a multi-axis force stick adapted to be held by the hand of the pilot for providing output signals indicative of forces applied to the stick in at least three distinct stick axes, each of said stick axes corresponding to a related one of said aircraft control axes; and a plurality of signal processing channels, each connected for response to the output signal related to a corresponding one of said stick axes, each providing a related desired position command signal to said positioning means which is the summation of a proportional function of the related force stick output signal and an integral function of the related force stick output signal, for providing manual control of the aircraft by flying to a floating trim point established by force inputs to said force stick, the integral portion of each desired position control signal establishing the trim point for each axis and the proportional portion of each desired position control signal causing deviation from the trim point in such axis.