Angle-of-Attack Command Longitudinal Control for Supersonic Advanced Trainer Aircraft

This paper details the design procedure of developing an angle-of attack command longitudinal control system for the relaxed static stability aircraft in power approach mode. An advanced method of relaxed static stability is utilized for improving aerodynamic performance of a supersonic advanced trainer aircraft. The trainer aircraft adopts the relaxed static stability concept to improve the aerodynamic performance and to guarantee the aircraft stability. The longitudinal control law of the aircraft uses the dynamic inversion and proportional-plus-integral control methods. This paper addresses the analysis of the aircraft characteristics such as damping ratio, natural frequency, and gain and phase margins about the state variables for the longitudinal inner loop feedback design. In numerical simulations, the flight control performance of the developed angle-of-attack command longitudinal control system is compared with that of the existing pitch rate command longitudinal control system.