Disturbance Decoupling Control for Flexible Air-Breathing Hypersonic Vehicles with Mismatched Condition

The disturbance decoupling control method is investigated for flight control of a flexible air-breathing hypersonic vehicle (FAHV). First, the longitudinal dynamics of the FAHV are simplified into nonlinear forms with mismatched system disturbances. Then a new nonlinear disturbance observer base on hyperbolic sine function is applied to estimate the mismatched disturbances. The disturbance decoupling control law for flight control of FAHV is deduced theoretically and its proof is provided. Finally, the stability of the closed-loop control system under the action of disturbance decoupling control law is proved by Lyapunov stability theory. Simulation results exhibit the performance and effectiveness of the proposed disturbance decoupling control law.