A study on longitudinal control law design and flying quality parameter optimization for highly maneuverable fighter

Abstract

Flight control law design aims to determine the optimal flying qualities and ensure the stability of aircraft for all mission task elements (MTE) over the entire flight envelope. Numerous control law design criteria offer guidance in the control law development process, and representative aircraft design criteria are presented in MIL-STD-1797 and MIL-DTL-9490E. This paper describes three design methods to optimize flying quality parameters in INDI (Incremental Nonlinear Dynamic Inversion) control based on the T-50 Advanced Supersonic Trainer aircraft model. In the first method, flying quality parameters are optimized to meet the flying-quality as a design goal. In the second method, flying quality parameters are optimized to have flying quality and stability margin, such as the gains and phase margins, as a design goal. In the last method, a lead-compensation filter is added at the feedback stage of the angular acceleration to improve the stability margin and then, flying quality parameter is re-optimized with the above second optimization method. The results of the design and evaluation show that the second and third optimization methods are better than the first, achieving level 1 flying quality and guaranteeing the aircraft's stability. ? ICROS 2018.