Automatic flight control pilot assist system

Claim 1

For use in an aircraft having an autopilot for providing one or more flight command signals and further having a manually operable device mechanically coupled through appropriate linkages to a flight control surface so as to afford positioning of said surface, the apparatus comprising: (i) signal combining first means for receiving a command signal S at from the autopilot, and (b) a signal S m , and for combining S m and S at in a predetermined phase relationship, (ii) second means connected for receiving a control signal S cp from said first means and comprising: (a) servomotor means connected to said linkages so as to operate in parallel with said manually operable device; (b) means for receiving S cp and a feedback signal and producing therefrom a corrective error signal S ep for causing the servomotor output position to change; (c) sensing means comprising circuit means, responsive to S ep , for providing a signal S x indicative of the excess of S ep over a predetermined reference R 1 , said excess being caused by a sufficient manual force being applied through said manually operable device and through said linkages to said flight control surface, (d) feedback circuit means for receiving the parallel servomotor output and signal S x and in response thereto producing said feedback signal, said feedback circuit means responding to signal S x and to the parallel servomotor output such that S x and the parallel servomotor output evoke oppositely phased components of said feedback signal; and (iii) third means, responsive to S x , for producing a signal simulative of the changes in the autopilot command signal S at which result from the aircraft responding to the manual force, the change-simulative signal provided by said third means being the signal S m , and said predetermined phase relationship in which S m and S at are combined by said first means being a phase relationship such that S m and said changes in S at tend to cancel one another.