Model Predictive Control Design for Tilt-Rotor Aircraft at Low Speed Flight

Control design in the longitudinal-vertical channel is studied for tilt-rotor aircraft at low speed flight. The famous XV-15 tilt-rotor aircraft is used as a prototype. A model predictive control (MPC) design is developed based on a state-space model in a cascaded architecture. The MPC algorithm considers a terminal cost in its objective function so as to ensure close-loop stability, and an error-rate term is introduced in order to improve transient performance. By transforming constraints, the controller designed based on a linearized model at single operating point is applied to the whole stage at low speed flight. It means that there is not switching as gain scheduling in the realization of the longitudinal control. The simulation results show that the flight control system presents satisfied performance and robustness.