Nonlinear μ flight control and suboptimal exact solution on F-16 application

This paper investigates the theory of nonlinear H_∞ analysis to flight vehicles with varying real parameters which arise from the uncertain aerodynamic coefficients. It's so called nonlinear μ flight control. The difficult task involved in applying the nonlinear μ light control is to solve the associated Hamilton-Jacobi inequality for uncertain system. In this paper we derive the suboptimal condition to meet the L ₂-gain of the nonlinear uncertain system less than a constant γ. The complete six degree-of-freedom nonlinear equations of motion for F-16 aircraft are considered directly to design the nonlinear μ flight controller by treating the longitudinal and lateral motions as a whole. The associated Hamilton-Jacobi partial differential inequality is solved analytically, resulting in a nonlinear μ controller with simple proportional feedback structure. This paper verify that the derived nonlinear μ control law can ensure global flight envelop and asymptotical stability of the closed loop system with varying aerodynamic characteristics and have strong robustness against wind gusts with varying statistical characteristics.