Automatic loop-shaping method in NLQFT and its application in aircraft control

This paper proposes an improved automatic loop-shaping method in nonlinear quantitative feedback theory (NLQFT). Dynamic inversion (DI) is used to partially linearize the dynamics, and modify the plant templates. Based on genetic algorithms (GA), the lead compensation parameter is optimized. The optimized parameter is converted to pole-zero assignment to generate the robust optimal, less order controller in CAD IDE (the interactive design environment). In the light of angle of attack (AOA) control of F-16 aircraft with complicated and nonlinear features, the control laws demonstrate perfect performance by accurately following large AOA commands at flight speeds ranging from 53 to 150 m/s. Robustness is verified by including ±20% variations in pitching moment derivatives. The simulation results show that, compared to a fixed-gain, linear design, the proposed method eliminated actuator oscillations effectively, except that the max overshoot is increased.