This paper considers a statically stable unmanned aircraft that is equipped with only two aerodynamic control surfaces (called elevons) and one tractor-type propeller. A fault in either of the elevons must, therefore, be managed using only the other elevon and the throttle. Because the fault results in an underactuated aircraft, the reconfiguration possibilities are limited. This paper proposes a strategy of using the throttle for total energy control and the single operable elevon for lateral control. This paper then develops a fault-tolerant controller based on this strategy and demonstrates, via multiple flight tests, the autonomous guidance and final approach of this unmanned aircraft in the presence of a stuck elevon fault. The results indicate that it may be possible to control other aerial bodies, including larger aircraft, using one aerodynamic control surface.
Bibliographical noteFunding Information:
This work was supported by the National Science Foundation under grant NSF/CNS-1329390 entitled “CPS: Breakthrough: Collaborative Research: Managing Uncertainty in the Design of Safety-Critical Aviation Systems”. The first author acknowledges financial support from the University of Minnesota through the 2017–2018 Doctoral Dissertation Fellowship. The authors thank the following individuals: T. Colten of Sentera for donating the Vireo aircraft; C. Olson for the flight software, controller implementation, autoland trajectory, head-up display, and piloting; N. Carter, R. Condron, L. Heide, A. Mahon, C. Regan, and B. Taylor for the aircraft integration and testing; and R. Condron, E. Day, D. Dessens, A. Krause, and P. Wagner for proving single-surface flight using manual pilot control.