Nonlinear Dynamic Inversion Control of VTOL Tilt-Wing UAV

Tilt-wing vertical takeoff and landing (VTOL) UAV is a combination of long endurance and VTOL capability. The highly nonlinear dynamics and multi-actuator control during mode transition are the two key problems. The coupling between pitch angle and airspeed during transition is critical for the VTOL tilt-wing UAV. Firstly, the transition must ensure the control of the pitch angle. A nonlinear dynamic inversion (NDI) controller is designed to track pitch angle command. The controller is divided into fast and slow subsystems based on the principle of time-scale separation. Control allocation is used to deal with multi-actuators during mode transition. Simulation results show that, compared with the PID controller, the NDI controller can achieve better tracking performance, and it is robust to aerodynamic parameter perturbation.