Nonlinear path-following method for fixed-wing unmanned aerial vehicles

A path-following method for fixed-wing unmanned aerial vehicles (UAVs) is presented in this paper. This method consists of an outer guidance loop and an inner control loop. The guidance law relies on the idea of tracking a virtual target. The motion of the virtual target is explicitly specified. The main advantage of this guidance law is that it considers the maneuvering ability of the aircraft. The aircraft can asymptotically approach the defined path with smooth movements. Meanwhile, the aircraft can anticipate the upcoming transition of the flight path. Moreover, the inner adaptive flight control loop based on attractive manifolds can follow the command generated by the outer guidance loop. This adaptive control law introduces a first-order filter to avoid solving the partial differential equation in the immersion and invariance adaptive control. The performance of the proposed path-following method is validated by the numerical simulation.