Longitudinal auto‐landing controller design via adaptive backstepping

This paper presents an auto‐landing controller for glide‐slope tracking and the flare maneuver via adaptive backstepping design and describes a flight path command generator for indirect altitude control in order to provide precise altitude trajectories for auto‐landing of unmanned aerial vehicles (UAVs). Using the adaptive backstepping procedure to synthesize a glide‐slope tracking and flare maneuver control law is being used differently from designing the guidance and control loops separately in autopilot. An adaptive controller is proposed to control aircraft from glide‐slope to flare by following the flight path angle command for indirect altitude control via elevator and maintaining the constant airspeed control via throttle. Simulation results demonstrate that the adaptive auto‐landing controller is capable of effectively guiding the UAV along the flight path angle command under the presence of the wind turbulence.