Finite-time boundedness control of morphing aircraft based on switched systems approach

The attitude and altitude boundedness control problem is presented for the programmed sweeping process of a conceptual morphing aircraft with variable sweepback wings. The motion characteristic within the morphing phase is complicated as it includes inertia loads and large variations in both formal parameters and aerodynamic coefficients. The longitudinal nonlinear dynamics is approximated by the uncertain switched linear system with bounded external disturbances corresponding to a series of equilibrium points along the transition trajectory. The finite-time boundedness robust control is introduced to guarantee the flight stability instead of the traditional asymptotic stability. The sufficient conditions are proposed in the form of linear matrix inequalities to ensure the finite-time boundedness and robust performance for uncertain switched linear system. Then the finite-time robust state feedback control algorithm is provided for the morphing flight control. The devised technique is applied in a particular example of sweeping flight, and the simulation is developed with the nonlinear model and switched controllers. Simulation results show that the proposed approach is effective for the morphing flight and achieves a proper tradeoff between the control performance and elevator deflections.