A Method for Integrating Thrust-Vectoring and Actuated Forebody Strakes With Conventional Aerodynamic Controls on a High-Performance Fighter Airplane

TL;DR: In this article, a method for integrating several airplane controls to achieve cooperative operation is presented, which eliminates conflicting control motions, minimizes the number of feedback control gains, and reduces the complication of feedback gain schedules.

Abstract: A method, called pseudo controls, of integrating several airplane controls to achieve cooperative operation is presented. The method eliminates conflicting control motions, minimizes the number of feedback control gains, and reduces the complication of feedback gain schedules. The method is applied to the lateral/directional controls of a modified high-performance airplane. The airplane has a conventional set of aerodynamic controls, an experimental set of thrust-vectoring controls, and an experimental set of actuated forebody strakes. The experimental controls give the airplane additional control power for enhanced stability and maneuvering capabilities while flying over an expanded envelope, especially at high angles of attack. The flight controls are scheduled to generate independent body-axis control moments. These control moments are coordinated to produce stability-axis angular accelerations. Inertial coupling moments are compensated. Thrust-vectoring controls are engaged according to their effectiveness relative to that of the aerodynamic controls. Vane-relief logic removes steady and slowly varying commands from the thrust-vectoring controls to alleviate heating of the thrust turning devices. The actuated forebody strakes are engaged at high angles of attack. This report presents the forward-loop elements of a flight control system that positions the flight controls according to the desired stability-axis accelerations. This report does not include the generation of the required angular acceleration commands by means of pilot controls or the feedback of sensed airplane motions. F/A-18 High-alpha research vehicle (HARV); Actuated nose strakes for enhanced rolling (ANSER); Fighter aircraft; Flight controls; Airplane control; Control design; Thrust vectoring; Forebody strakes; Forebody controls; High angle of attack; Integrated control