IJCAS

The modeling and control problems for the conversion mode of tilt-rotor aircraft are discussed with a switched Takagi-Sugeno (T-S) fuzzy modeling method and an H∞ anti-disturbance tracking control design technique. First, a more general nonlinear motion equation of the conversion mode is deduced by taking the rotor effect into consideration. Second, a switched T-S fuzzy model with an exosystem is adopted to precisely approximate the nonlinear model with an uncontrolled tilting angle. Furthermore, the mast angle is chosen as the premise variable to improve the model accuracy. On this foundation, the conversion mode control problem is transformed to a state tracking control design of the obtained switched T-S fuzzy system. Third, in order to improve the tracking performance, an H∞ anti-disturbance control scheme is proposed, which includes the switched T-S fuzzy controller and the disturbance observer. In this way, both internal and external disturbances can be attenuated. Finally, the simulation result with respect to the XV-15 tilt-rotor aircraft is provided to illustrate the effectiveness and merits of the developed modeling and control scheme.

Keywords: Conversion mode, fuzzy disturbance observer, H∞ anti-disturbance tracking control, switched T-S fuzzy modeling, tilt-rotor aircraft.