Robust Design of Transition Flight Control System with Input Constraint

This paper proposed a new flight control system for transition flight of fixed-wing unmanned aerial vehicle (UAV). Robust controllers are designed for translational motion and rotational motion of a small fixed-wing UAV. Each nonlinear equation is linearized by using dynamic inversion method in the translational and the rotational control systems. An observer based on disturbance accommodating control methodologies and extended Kalman filter are treated to estimate nonlinear terms and state variables of a UAV dynamic system, respectively. We apply the anti-windup control to the control system so as to implement input saturation that might result in system instability. Numerical and flight test results showed that a developed UAV was stably controlled without the saturation during transition flight.