Autonomous landing of a fixed-Wing unmanned aircraft with partialwing and stabiliser losses

Hugo, Gideon (2017-03)

Thesis (MEng)--Stellenbosch University, 2017.

Thesis

ENGLISH ABSTRACT: This thesis presents the design, implementation and verification of an autonomous landing system for a fixed-wing unmanned aerial vehicle that is able to land the aircraft after suffering partial wing loss and partial losses of the horizontal and vertical stabilisers. A fault-tolerant flight control system is designed, which ensures that the inner-loop controllers remain stable and within acceptable transient response specifications when the aircraft suffers partial wing, horizontal stabiliser, and vertical stabiliser losses. The design approach is to find controller gains that provide the best performance for the undamaged aircraft, while still providing at least the minimum acceptable performance over all damage cases. An algorithm calculates the controller gains, if such gains exist, with different combinations of natural frequencies and damping ratios for all damage cases until both the desired closed-loop performance and robustness are obtained. Autonomous landing is accomplished using a state machine that guides the aircraft through the landing phases. The flight control laws, waypoint navigation, and autonomous landing system were verified in simulation and with practical flight tests. Landing accuracies within a 1.5 m radius circle are accomplished in simulation for an aircraft with 20% wing loss, 70% horizontal stabiliser loss, and 20% vertical stabiliser loss.

AFRIKAANSE OPSOMMING: Hierdie tesis beskryf die ontwerp, implementering en verifiëring van ’n outonome landingstelsel vir ’n vastevlerk-onbemande vliegtuig wat in staat is om die vliegtuig te land nadat dit gedeeltelike vlerkverlies en gedeeltelike verlies van die horisontale en vertikale stabiliseerders ervaar het. ’n Fout-tolerante vlugbeheerstelsel is ontwerp wat verseker dat die binnelusbeheerders stabiel en binne aanvaarbare oorgansverskynsel-spesifikasies bly wanneer die vliegtuig hierdie verliese ervaar. Die ontwerps benadering is om beheerder-aanwinste te vind wat die beste oorgangsverskynsels vir die onbeskadigde vliegtuig haal, terwyl die aanwinste nog ten minste die minimum aanvaarbare oorgangsverskynsels oor al die verlies gevalle haal. ’n Iteratiewe algoritme bereken die beheerder-aanwinste, indien sodanige aanwinste bestaan, met verskillende kombinasies van natuurlike frekwensies en dempings verhoudings vir alle skadegevalle tot beide die gewenste geslotelusgedrag en robuustheid verkry word. Die outonome landing word uitgevoer met behulp van ’n toestandsmasjien wat die vliegtuig deur die landingsfases neem. Die vlugbeheerwette en landingstelsel word deur simulasie geverifieer, asook deur praktiese vlugtoetse. ’n Landingsakkuraatheid binne ’n sirkel van 1.5 m radius word in simulasie behaal vir ’n vliegtuig met 20 % vlerkverlies, 70 % horisontale stabiliseerderverlies, en 20 % vertikale stabiliseerderverlies.

Please refer to this item in SUNScholar by using the following persistent URL: http://hdl.handle.net/10019.1/101035
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