Automatic landing of aircraft is a challenging guidance and control task that requires multiple feedback loops and a precise sequence of actions. Increasing operational flexibility and reducing the dependence on external infrastructure are key challenges for future unmanned aircraft. Usually, an aircraft performs the final approach on a straight line. This paper contributes a complete automatic landing controller capable of using three-dimensional curved approach paths all the way until touchdown. The controller consists of a nonlinear guidance law that steers the aircraft along a predefined spline path, various single-input–single-output control loops for rate and attitude control, and a robust multivariable flare controller. This flare controller ensures a three-point landing, i.e., simultaneous touchdown of all three wheels. Further, practical issues such as bumpless mode transfer and anti-windup compensation are considered. The controller is evaluated in multiple flight test experiments. Both the crabbed approach and the sideslip technique are demonstrated on several different approach paths, such as a steep curve and a helix. These paths are particularly challenging, because the flare maneuver is performed while the aircraft is in a turn. The controller is shown to reliably land the aircraft on an unpaved runway with high precision.
Flight Testing Automatic Landing Control for Unmanned Aircraft Including Curved Approaches
Journal of Guidance, Control, and Dynamics ; 45 , 4 ; 726-739
2021-11-10
14 pages
Aufsatz (Zeitschrift)
Elektronische Ressource
Englisch
Flight testing automatic landing control for unmanned aircraft including curved approaches
BASE | 2021
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